21919944 has 16 divisors (see below), whose sum is σ = 54799920. Its totient is φ = 7306640.

The previous prime is 21919927. The next prime is 21919951. The reversal of 21919944 is 44991912.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 456642 + ... + 456689.

It is an arithmetic number, because the mean of its divisors is an integer number (3424995).

Almost surely, 2^21919944 is an apocalyptic number.

21919944 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21919944 is an abundant number, since it is smaller than the sum of its proper divisors (32879976).

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

21919944 is a wasteful number, since it uses less digits than its factorization.

21919944 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 913340 (or 913336 counting only the distinct ones).

The product of its digits is 23328, while the sum is 39.

The square root of 21919944 is about 4681.8739837804. The cubic root of 21919944 is about 279.8636410875.

The spelling of 21919944 in words is "twenty-one million, nine hundred nineteen thousand, nine hundred forty-four".