21357264 has 60 divisors (see below), whose sum is σ = 57133248. Its totient is φ = 6874560.

The previous prime is 21357263. The next prime is 21357299. The reversal of 21357264 is 46275312.

It is a super-2 number, since 2×21357264² = 912265451131392, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21357263) 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 11 ways as a sum of consecutive naturals, for example, 45897 + ... + 46359.

Almost surely, 2^21357264 is an apocalyptic number.

21357264 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21357264, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28566624).

21357264 is an abundant number, since it is smaller than the sum of its proper divisors (35775984).

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

21357264 is a wasteful number, since it uses less digits than its factorization.

21357264 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 536 (or 499 counting only the distinct ones).

The product of its digits is 10080, while the sum is 30.

The square root of 21357264 is about 4621.3919980889. The cubic root of 21357264 is about 277.4481747224.

The spelling of 21357264 in words is "twenty-one million, three hundred fifty-seven thousand, two hundred sixty-four".