21099264 has 72 divisors (see below), whose sum is σ = 57003072. Its totient is φ = 6927360.

The previous prime is 21099187. The next prime is 21099277. The reversal of 21099264 is 46299012.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 63579 + ... + 63909.

Almost surely, 2^21099264 is an apocalyptic number.

21099264 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 21099264, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28501536).

21099264 is an abundant number, since it is smaller than the sum of its proper divisors (35903808).

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

21099264 is an equidigital number, since it uses as much as digits as its factorization.

21099264 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 433 (or 419 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 33.

The square root of 21099264 is about 4593.3935167804. The cubic root of 21099264 is about 276.3264358557.

The spelling of 21099264 in words is "twenty-one million, ninety-nine thousand, two hundred sixty-four".