21616025633666 has 16 divisors (see below), whose sum is σ = 33304265497656. Its totient is φ = 10514672251776.

The previous prime is 21616025633641. The next prime is 21616025633689. The reversal of 21616025633666 is 66633652061612.

It can be written as a sum of positive squares in 4 ways, for example, as 21232548878641 + 383476755025 = 4607879^2 + 619255^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16476641 + ... + 17740116.

Almost surely, 2^{21616025633666} is an apocalyptic number.

21616025633666 is a deficient number, since it is larger than the sum of its proper divisors (11688239863990).

21616025633666 is a wasteful number, since it uses less digits than its factorization.

21616025633666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34225333.

The product of its (nonzero) digits is 8398080, while the sum is 53.

The spelling of 21616025633666 in words is "twenty-one trillion, six hundred sixteen billion, twenty-five million, six hundred thirty-three thousand, six hundred sixty-six".