21211566216 has 16 divisors (see below), whose sum is σ = 53028915600. Its totient is φ = 7070522064.

The previous prime is 21211566203. The next prime is 21211566227. The reversal of 21211566216 is 61266511212.

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, 441907606 + ... + 441907653.

It is an arithmetic number, because the mean of its divisors is an integer number (3314307225).

Almost surely, 2^21211566216 is an apocalyptic number.

It is an amenable number.

21211566216 is an abundant number, since it is smaller than the sum of its proper divisors (31817349384).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21211566216 is a wasteful number, since it uses less digits than its factorization.

21211566216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 883815268 (or 883815264 counting only the distinct ones).

The product of its digits is 8640, while the sum is 33.

The spelling of 21211566216 in words is "twenty-one billion, two hundred eleven million, five hundred sixty-six thousand, two hundred sixteen".