21055623616 has 56 divisors (see below), whose sum is σ = 42116386176. Its totient is φ = 10443820800.

The previous prime is 21055623587. The next prime is 21055623731. The reversal of 21055623616 is 61632655012.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12630015 + ... + 12631681.

Almost surely, 2^21055623616 is an apocalyptic number.

It is an amenable number.

21055623616 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

21055623616 is a wasteful number, since it uses less digits than its factorization.

21055623616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3137 (or 3127 counting only the distinct ones).

The product of its (nonzero) digits is 64800, while the sum is 37.

The spelling of 21055623616 in words is "twenty-one billion, fifty-five million, six hundred twenty-three thousand, six hundred sixteen".