18641581056 has 440 divisors, whose sum is σ = 64469953856. Its totient is φ = 5255331840.

The previous prime is 18641581043. The next prime is 18641581061. The reversal of 18641581056 is 65018514681.

18641581056 is a `hidden beast` number, since 1 + 8 + 64 + 1 + 581 + 0 + 5 + 6 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 56318811 + ... + 56319141.

Almost surely, 2^18641581056 is an apocalyptic number.

18641581056 is a gapful number since it is divisible by the number (16) 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 18641581056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32234976928).

18641581056 is an abundant number, since it is smaller than the sum of its proper divisors (45828372800).

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

18641581056 is an equidigital number, since it uses as much as digits as its factorization.

18641581056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 467 (or 440 counting only the distinct ones).

The product of its (nonzero) digits is 230400, while the sum is 45.

The spelling of 18641581056 in words is "eighteen billion, six hundred forty-one million, five hundred eighty-one thousand, fifty-six".