641872 has 40 divisors (see below), whose sum is σ = 1553472. Its totient is φ = 249600.

The previous prime is 641867. The next prime is 641873. The reversal of 641872 is 278146.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 641872.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641873) by changing a digit.

641872 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 7 ways as a sum of consecutive naturals, for example, 972 + ... + 1492.

2⁶⁴¹⁸⁷² 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 641872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (776736).

641872 is an abundant number, since it is smaller than the sum of its proper divisors (911600).

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

641872 is a wasteful number, since it uses less digits than its factorization.

641872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 547 (or 541 counting only the distinct ones).

The product of its digits is 2688, while the sum is 28.

The square root of 641872 is about 801.1691456865. The cubic root of 641872 is about 86.2613287647.

It can be divided in two parts, 64 and 1872, that added together give a square (1936 = 44²).

The spelling of 641872 in words is "six hundred forty-one thousand, eight hundred seventy-two".