21165212 has 6 divisors (see below), whose sum is σ = 37039128. Its totient is φ = 10582604.

The previous prime is 21165197. The next prime is 21165227. The reversal of 21165212 is 21256112.

It is an interprime number because it is at equal distance from previous prime (21165197) and next prime (21165227).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2645648 + ... + 2645655.

It is an arithmetic number, because the mean of its divisors is an integer number (6173188).

Almost surely, 2^21165212 is an apocalyptic number.

It is an amenable number.

21165212 is a deficient number, since it is larger than the sum of its proper divisors (15873916).

21165212 is a wasteful number, since it uses less digits than its factorization.

21165212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5291307 (or 5291305 counting only the distinct ones).

The product of its digits is 240, while the sum is 20.

The square root of 21165212 is about 4600.5664868579. The cubic root of 21165212 is about 276.6140323414.

The spelling of 21165212 in words is "twenty-one million, one hundred sixty-five thousand, two hundred twelve".