21437164 has 12 divisors (see below), whose sum is σ = 42874384. Its totient is φ = 9187344.

The previous prime is 21437161. The next prime is 21437167. The reversal of 21437164 is 46173412.

It is an interprime number because it is at equal distance from previous prime (21437161) and next prime (21437167).

21437164 is an admirable number.

It is a Harshad number since it is a multiple of its sum of digits (28), and also a Moran number because the ratio is a prime number: 765613 = 21437164 / (2 + 1 + 4 + 3 + 7 + 1 + 6 + 4).

It is not an unprimeable number, because it can be changed into a prime (21437161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 382779 + ... + 382834.

Almost surely, 2^21437164 is an apocalyptic number.

It is an amenable number.

21437164 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21437164 is a wasteful number, since it uses less digits than its factorization.

21437164 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 765624 (or 765622 counting only the distinct ones).

The product of its digits is 4032, while the sum is 28.

The square root of 21437164 is about 4630.0285096314. The cubic root of 21437164 is about 277.7937327487.

The spelling of 21437164 in words is "twenty-one million, four hundred thirty-seven thousand, one hundred sixty-four".