21719344 has 20 divisors (see below), whose sum is σ = 43439680. Its totient is φ = 10509120.

The previous prime is 21719339. The next prime is 21719351. The reversal of 21719344 is 44391712.

21719344 is an admirable number.

It is a Harshad number since it is a multiple of its sum of digits (31).

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 3 ways as a sum of consecutive naturals, for example, 21399 + ... + 22390.

It is an arithmetic number, because the mean of its divisors is an integer number (2171984).

Almost surely, 2^21719344 is an apocalyptic number.

It is an amenable number.

21719344 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21719344 is a wasteful number, since it uses less digits than its factorization.

21719344 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43828 (or 43822 counting only the distinct ones).

The product of its digits is 6048, while the sum is 31.

The square root of 21719344 is about 4660.4016994246. The cubic root of 21719344 is about 279.0073010170.

The spelling of 21719344 in words is "twenty-one million, seven hundred nineteen thousand, three hundred forty-four".