21266164 has 12 divisors (see below), whose sum is σ = 38499300. Its totient is φ = 10266368.

The previous prime is 21266129. The next prime is 21266171. The reversal of 21266164 is 46166212.

It can be written as a sum of positive squares in 2 ways, for example, as 16337764 + 4928400 = 4042^2 + 2220^2 .

It is a congruent number.

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, 91549 + ... + 91780.

It is an arithmetic number, because the mean of its divisors is an integer number (3208275).

Almost surely, 2^21266164 is an apocalyptic number.

It is an amenable number.

21266164 is a deficient number, since it is larger than the sum of its proper divisors (17233136).

21266164 is a wasteful number, since it uses less digits than its factorization.

21266164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 183362 (or 183360 counting only the distinct ones).

The product of its digits is 3456, while the sum is 28.

The square root of 21266164 is about 4611.5251273304. The cubic root of 21266164 is about 277.0531248705.

The spelling of 21266164 in words is "twenty-one million, two hundred sixty-six thousand, one hundred sixty-four".