21615066884 has 6 divisors (see below), whose sum is σ = 37826367054. Its totient is φ = 10807533440.

The previous prime is 21615066871. The next prime is 21615066917. The reversal of 21615066884 is 48866051612.

It can be written as a sum of positive squares in only one way, i.e., 21597241600 + 17825284 = 146960^2 + 4222^2 .

It is a super-2 number, since 2×21615066884² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2701883357 + ... + 2701883364.

It is an arithmetic number, because the mean of its divisors is an integer number (6304394509).

Almost surely, 2^21615066884 is an apocalyptic number.

It is an amenable number.

21615066884 is a deficient number, since it is larger than the sum of its proper divisors (16211300170).

21615066884 is a wasteful number, since it uses less digits than its factorization.

21615066884 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5403766725 (or 5403766723 counting only the distinct ones).

The product of its (nonzero) digits is 552960, while the sum is 47.

The spelling of 21615066884 in words is "twenty-one billion, six hundred fifteen million, sixty-six thousand, eight hundred eighty-four".