21666980997028 has 12 divisors (see below), whose sum is σ = 37984565268720. Its totient is φ = 10814248063112.

The previous prime is 21666980997019. The next prime is 21666980997047. The reversal of 21666980997028 is 82079908966612.

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, 4810606318 + ... + 4810610821.

It is an arithmetic number, because the mean of its divisors is an integer number (3165380439060).

Almost surely, 2^{21666980997028} is an apocalyptic number.

It is an amenable number.

21666980997028 is a deficient number, since it is larger than the sum of its proper divisors (16317584271692).

21666980997028 is a wasteful number, since it uses less digits than its factorization.

21666980997028 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9621217706 (or 9621217704 counting only the distinct ones).

The product of its (nonzero) digits is 282175488, while the sum is 73.

The spelling of 21666980997028 in words is "twenty-one trillion, six hundred sixty-six billion, nine hundred eighty million, nine hundred ninety-seven thousand, twenty-eight".