21715344 has 160 divisors (see below), whose sum is σ = 73328640. Its totient is φ = 6023808.

The previous prime is 21715339. The next prime is 21715357. The reversal of 21715344 is 44351712.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 129949 + ... + 130115.

It is an arithmetic number, because the mean of its divisors is an integer number (458304).

Almost surely, 2^21715344 is an apocalyptic number.

21715344 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 21715344, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36664320).

21715344 is an abundant number, since it is smaller than the sum of its proper divisors (51613296).

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

21715344 is a wasteful number, since it uses less digits than its factorization.

21715344 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 234 (or 222 counting only the distinct ones).

The product of its digits is 3360, while the sum is 27.

The square root of 21715344 is about 4659.9725321079. The cubic root of 21715344 is about 278.9901719281.

The spelling of 21715344 in words is "twenty-one million, seven hundred fifteen thousand, three hundred forty-four".