21216166226625 has 128 divisors (see below), whose sum is σ = 35809532328960. Its totient is φ = 11154302208000.

The previous prime is 21216166226597. The next prime is 21216166226627. The reversal of 21216166226625 is 52662266161212.

It is not a de Polignac number, because 21216166226625 - 2¹⁶ = 21216166161089 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21216166226627) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 9252578979 + ... + 9252581271.

It is an arithmetic number, because the mean of its divisors is an integer number (279761971320).

Almost surely, 2^{21216166226625} is an apocalyptic number.

21216166226625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21216166226625 is a deficient number, since it is larger than the sum of its proper divisors (14593366102335).

21216166226625 is a wasteful number, since it uses less digits than its factorization.

21216166226625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3404 (or 3394 counting only the distinct ones).

The product of its digits is 1244160, while the sum is 48.

The spelling of 21216166226625 in words is "twenty-one trillion, two hundred sixteen billion, one hundred sixty-six million, two hundred twenty-six thousand, six hundred twenty-five".