21561054016 has 28 divisors (see below), whose sum is σ = 42914519200. Its totient is φ = 10747946880.

The previous prime is 21561053989. The next prime is 21561054019. The reversal of 21561054016 is 61045016512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21561054019) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 487716 + ... + 530083.

It is an arithmetic number, because the mean of its divisors is an integer number (1532661400).

Almost surely, 2^21561054016 is an apocalyptic number.

It is an amenable number.

21561054016 is a deficient number, since it is larger than the sum of its proper divisors (21353465184).

21561054016 is a wasteful number, since it uses less digits than its factorization.

21561054016 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1018142 (or 1018132 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 31.

The spelling of 21561054016 in words is "twenty-one billion, five hundred sixty-one million, fifty-four thousand, sixteen".