641558556 has 90 divisors (see below), whose sum is σ = 1711028088. Its totient is φ = 209578320.

The previous prime is 641558539. The next prime is 641558557. The reversal of 641558556 is 655855146.

641558556 is a `hidden beast` number, since 6 + 4 + 15 + 585 + 56 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641558557) by changing a digit.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 3841585 + ... + 3841751.

Almost surely, 2^641558556 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 641558556, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (855514044).

641558556 is an abundant number, since it is smaller than the sum of its proper divisors (1069469532).

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

641558556 is a wasteful number, since it uses less digits than its factorization.

641558556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 421 (or 243 counting only the distinct ones).

The product of its digits is 720000, while the sum is 45.

The square root of 641558556 is about 25329.0062181681. The cubic root of 641558556 is about 862.4728520756.

The spelling of 641558556 in words is "six hundred forty-one million, five hundred fifty-eight thousand, five hundred fifty-six".