Search a number
-
+
639972 = 223229613
BaseRepresentation
bin10011100001111100100
31012111212200
42130033210
5130434342
621414500
75303544
oct2341744
91174780
10639972
113a7903
1226a430
131953a8
14129324
15c994c
hex9c3e4

639972 has 36 divisors (see below), whose sum is σ = 1676220. Its totient is φ = 205632.

The previous prime is 639959. The next prime is 639983. The reversal of 639972 is 279936.

639972 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 112896 + 527076 = 336^2 + 726^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a d-powerful number, because it can be written as 66 + 312 + 93 + 95 + 72 + 211 .

It is a congruent number.

It is an unprimeable number.

639972 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 738 + ... + 1350.

2639972 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 639972, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (838110).

639972 is an abundant number, since it is smaller than the sum of its proper divisors (1036248).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

639972 is a wasteful number, since it uses less digits than its factorization.

639972 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 652 (or 647 counting only the distinct ones).

The product of its digits is 20412, while the sum is 36.

The square root of 639972 is about 799.9824998086. The cubic root of 639972 is about 86.1761308294.

Subtracting from 639972 its sum of digits (36), we obtain a palindrome (639936).

The spelling of 639972 in words is "six hundred thirty-nine thousand, nine hundred seventy-two".

Divisors: 1 2 3 4 6 9 12 18 29 36 58 87 116 174 261 348 522 613 1044 1226 1839 2452 3678 5517 7356 11034 17777 22068 35554 53331 71108 106662 159993 213324 319986 639972