21012655104 has 792 divisors, whose sum is σ = 77661542400. Its totient is φ = 5434490880.

The previous prime is 21012655099. The next prime is 21012655109. The reversal of 21012655104 is 40155621012.

21012655104 is a `hidden beast` number, since 2 + 1 + 0 + 1 + 2 + 655 + 1 + 0 + 4 = 666.

It is an interprime number because it is at equal distance from previous prime (21012655099) and next prime (21012655109).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012655109) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 265982937 + ... + 265983015.

Almost surely, 2^21012655104 is an apocalyptic number.

21012655104 is a gapful number since it is divisible by the number (24) 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 21012655104, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38830771200).

21012655104 is an abundant number, since it is smaller than the sum of its proper divisors (56648887296).

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

21012655104 is a wasteful number, since it uses less digits than its factorization.

21012655104 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 169 (or 141 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 27.

The spelling of 21012655104 in words is "twenty-one billion, twelve million, six hundred fifty-five thousand, one hundred four".