21153264 has 40 divisors (see below), whose sum is σ = 59615232. Its totient is φ = 6409920.

The previous prime is 21153263. The next prime is 21153281. The reversal of 21153264 is 46235112.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21153263) by changing a digit.

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, 19504 + ... + 20559.

Almost surely, 2^21153264 is an apocalyptic number.

21153264 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21153264 is an abundant number, since it is smaller than the sum of its proper divisors (38461968).

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

21153264 is a wasteful number, since it uses less digits than its factorization.

21153264 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40085 (or 40079 counting only the distinct ones).

The product of its digits is 1440, while the sum is 24.

The square root of 21153264 is about 4599.2677678083. The cubic root of 21153264 is about 276.5619719675.

Adding to 21153264 its reverse (46235112), we get a palindrome (67388376).

The spelling of 21153264 in words is "twenty-one million, one hundred fifty-three thousand, two hundred sixty-four".