21166235204 has 18 divisors (see below), whose sum is σ = 37922374350. Its totient is φ = 10336994976.

The previous prime is 21166235197. The next prime is 21166235297. The reversal of 21166235204 is 40253266112.

It can be written as a sum of positive squares in only one way, i.e., 18183983104 + 2982252100 = 134848^2 + 54610^2 .

It is a super-2 number, since 2×21166235204² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1423529 + ... + 1438320.

It is an arithmetic number, because the mean of its divisors is an integer number (2106798575).

Almost surely, 2^21166235204 is an apocalyptic number.

It is an amenable number.

21166235204 is a deficient number, since it is larger than the sum of its proper divisors (16756139146).

21166235204 is a wasteful number, since it uses less digits than its factorization.

21166235204 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2861939 (or 2861894 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 32.

The spelling of 21166235204 in words is "twenty-one billion, one hundred sixty-six million, two hundred thirty-five thousand, two hundred four".