21229164 has 36 divisors (see below), whose sum is σ = 58542120. Its totient is φ = 6432960.

The previous prime is 21229163. The next prime is 21229177. The reversal of 21229164 is 46192212.

It is a tau number, because it is divible by the number of its divisors (36).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (21229163) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 26409 + ... + 27200.

It is an arithmetic number, because the mean of its divisors is an integer number (1626170).

Almost surely, 2^21229164 is an apocalyptic number.

It is an amenable number.

21229164 is an abundant number, since it is smaller than the sum of its proper divisors (37312956).

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

21229164 is a wasteful number, since it uses less digits than its factorization.

21229164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53630 (or 53625 counting only the distinct ones).

The product of its digits is 1728, while the sum is 27.

The square root of 21229164 is about 4607.5116928772. The cubic root of 21229164 is about 276.8923543552.

The spelling of 21229164 in words is "twenty-one million, two hundred twenty-nine thousand, one hundred sixty-four".