21515263422561 has 40 divisors (see below), whose sum is σ = 32594130676800. Its totient is φ = 14140893906720.

The previous prime is 21515263422553. The next prime is 21515263422589. The reversal of 21515263422561 is 16522436251512.

21515263422561 is a `hidden beast` number, since 2 + 1 + 5 + 1 + 5 + 2 + 63 + 4 + 22 + 561 = 666.

It is not a de Polignac number, because 21515263422561 - 2³ = 21515263422553 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21515263422551) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 168262110 + ... + 168389928.

It is an arithmetic number, because the mean of its divisors is an integer number (814853266920).

Almost surely, 2^{21515263422561} is an apocalyptic number.

It is an amenable number.

21515263422561 is a deficient number, since it is larger than the sum of its proper divisors (11078867254239).

21515263422561 is a wasteful number, since it uses less digits than its factorization.

21515263422561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157171 (or 157162 counting only the distinct ones).

The product of its digits is 864000, while the sum is 45.

The spelling of 21515263422561 in words is "twenty-one trillion, five hundred fifteen billion, two hundred sixty-three million, four hundred twenty-two thousand, five hundred sixty-one".