21415264 has 24 divisors (see below), whose sum is σ = 45405360. Its totient is φ = 9883776.

The previous prime is 21415249. The next prime is 21415307. The reversal of 21415264 is 46251412.

It is a happy number.

It is a super-2 number, since 2×21415264² = 917227064379392, which contains 22 as substring.

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, 25324 + ... + 26155.

It is an arithmetic number, because the mean of its divisors is an integer number (1891890).

Almost surely, 2^21415264 is an apocalyptic number.

It is an amenable number.

21415264 is an abundant number, since it is smaller than the sum of its proper divisors (23990096).

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

21415264 is a wasteful number, since it uses less digits than its factorization.

21415264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51502 (or 51494 counting only the distinct ones).

The product of its digits is 1920, while the sum is 25.

The square root of 21415264 is about 4627.6629090719. The cubic root of 21415264 is about 277.6991033845.

Adding to 21415264 its reverse (46251412), we get a palindrome (67666676).

The spelling of 21415264 in words is "twenty-one million, four hundred fifteen thousand, two hundred sixty-four".