21111615064 has 16 divisors (see below), whose sum is σ = 40061198520. Its totient is φ = 10428628800.

The previous prime is 21111615059. The next prime is 21111615079. The reversal of 21111615064 is 46051611112.

It is a super-2 number, since 2×21111615064² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15896637 + ... + 15897964.

Almost surely, 2^21111615064 is an apocalyptic number.

It is an amenable number.

21111615064 is a deficient number, since it is larger than the sum of its proper divisors (18949583456).

21111615064 is a wasteful number, since it uses less digits than its factorization.

21111615064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31794690 (or 31794686 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 28.

The spelling of 21111615064 in words is "twenty-one billion, one hundred eleven million, six hundred fifteen thousand, sixty-four".