641258640 has 320 divisors, whose sum is σ = 2439486720. Its totient is φ = 153538560.

The previous prime is 641258633. The next prime is 641258641. The reversal of 641258640 is 46852146.

641258640 is a `hidden beast` number, since 6 + 4 + 1 + 2 + 5 + 8 + 640 = 666.

It is a super-2 number, since 2×641258640² = 822425286749299200, which contains 22 as substring.

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

It is a junction number, because it is equal to n+sod(n) for n = 641258595 and 641258604.

It is not an unprimeable number, because it can be changed into a prime (641258641) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 3255022 + ... + 3255218.

It is an arithmetic number, because the mean of its divisors is an integer number (7623396).

Almost surely, 2^641258640 is an apocalyptic number.

641258640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 641258640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1219743360).

641258640 is an abundant number, since it is smaller than the sum of its proper divisors (1798228080).

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

641258640 is a wasteful number, since it uses less digits than its factorization.

641258640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 367 (or 355 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 36.

The square root of 641258640 is about 25323.0851201034. The cubic root of 641258640 is about 862.3384347655.

The spelling of 641258640 in words is "six hundred forty-one million, two hundred fifty-eight thousand, six hundred forty".