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31001 = 291069
BaseRepresentation
bin111100100011001
31120112012
413210121
51443001
6355305
7156245
oct74431
946465
1031001
1121323
1215b35
1311159
14b425
1592bb
hex7919

31001 has 4 divisors (see below), whose sum is σ = 32100. Its totient is φ = 29904.

The previous prime is 30983. The next prime is 31013. The reversal of 31001 is 10013.

Adding to 31001 its reverse (10013), we get a palindrome (41014).

It can be divided in two parts, 3 and 1001, that multiplied together give a palindrome (3003).

31001 = 1242 + 1252.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 15376 + 15625 = 124^2 + 125^2 .

It is a cyclic number.

It is not a de Polignac number, because 31001 - 26 = 30937 is a prime.

It is a super-2 number, since 2×310012 = 1922124002, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

It is a Curzon number.

It is a plaindrome in base 13.

It is a nialpdrome in base 8.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31051) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 506 + ... + 563.

It is an arithmetic number, because the mean of its divisors is an integer number (8025).

231001 is an apocalyptic number.

31001 is the 125-th centered square number.

It is an amenable number.

31001 is a deficient number, since it is larger than the sum of its proper divisors (1099).

31001 is a wasteful number, since it uses less digits than its factorization.

31001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1098.

The product of its (nonzero) digits is 3, while the sum is 5.

The square root of 31001 is about 176.0710084029. The cubic root of 31001 is about 31.4141443031.

The spelling of 31001 in words is "thirty-one thousand, one".

Divisors: 1 29 1069 31001