21499264 has 32 divisors (see below), whose sum is σ = 43280640. Its totient is φ = 10636800.

The previous prime is 21499259. The next prime is 21499277. The reversal of 21499264 is 46299412.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (32).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12097 + ... + 13759.

It is an arithmetic number, because the mean of its divisors is an integer number (1352520).

Almost surely, 2^21499264 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21499264, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21640320).

21499264 is an abundant number, since it is smaller than the sum of its proper divisors (21781376).

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

21499264 is a wasteful number, since it uses less digits than its factorization.

21499264 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1778 (or 1766 counting only the distinct ones).

The product of its digits is 31104, while the sum is 37.

The square root of 21499264 is about 4636.7298821475. The cubic root of 21499264 is about 278.0617153324.

The spelling of 21499264 in words is "twenty-one million, four hundred ninety-nine thousand, two hundred sixty-four".