21566083515 has 16 divisors (see below), whose sum is σ = 36005983488. Its totient is φ = 11001827936.

The previous prime is 21566083447. The next prime is 21566083523. The reversal of 21566083515 is 51538066512.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21566083515 - 2⁷ = 21566083387 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 31254849 + ... + 31255538.

It is an arithmetic number, because the mean of its divisors is an integer number (2250373968).

Almost surely, 2^21566083515 is an apocalyptic number.

21566083515 is a deficient number, since it is larger than the sum of its proper divisors (14439899973).

21566083515 is a wasteful number, since it uses less digits than its factorization.

21566083515 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62510418.

The product of its (nonzero) digits is 216000, while the sum is 42.

The spelling of 21566083515 in words is "twenty-one billion, five hundred sixty-six million, eighty-three thousand, five hundred fifteen".