21646164 has 24 divisors (see below), whose sum is σ = 50740480. Its totient is φ = 7182144.

The previous prime is 21646139. The next prime is 21646189. The reversal of 21646164 is 46164612.

It is an interprime number because it is at equal distance from previous prime (21646139) and next prime (21646189).

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1369 + ... + 6720.

Almost surely, 2^21646164 is an apocalyptic number.

It is an amenable number.

21646164 is an abundant number, since it is smaller than the sum of its proper divisors (29094316).

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

21646164 is a wasteful number, since it uses less digits than its factorization.

21646164 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8319 (or 8317 counting only the distinct ones).

The product of its digits is 6912, while the sum is 30.

The square root of 21646164 is about 4652.5438203202. The cubic root of 21646164 is about 278.6935909772.

The spelling of 21646164 in words is "twenty-one million, six hundred forty-six thousand, one hundred sixty-four".