641986880 has 56 divisors (see below), whose sum is σ = 1557616392. Its totient is φ = 251942912.

The previous prime is 641986871. The next prime is 641986883. The reversal of 641986880 is 88689146.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 3717184 + 638269696 = 1928^2 + 25264^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641986883) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1967 + ... + 35886.

Almost surely, 2^641986880 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 641986880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (778808196).

641986880 is an abundant number, since it is smaller than the sum of its proper divisors (915629512).

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

641986880 is a wasteful number, since it uses less digits than its factorization.

641986880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37923 (or 37913 counting only the distinct ones).

The product of its (nonzero) digits is 663552, while the sum is 50.

The square root of 641986880 is about 25337.4600147686. The cubic root of 641986880 is about 862.6647470774.

The spelling of 641986880 in words is "six hundred forty-one million, nine hundred eighty-six thousand, eight hundred eighty".