21379944 has 32 divisors (see below), whose sum is σ = 54695520. Its totient is φ = 6960576.

The previous prime is 21379933. The next prime is 21379957. The reversal of 21379944 is 44997312.

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, 9327 + ... + 11390.

It is an arithmetic number, because the mean of its divisors is an integer number (1709235).

Almost surely, 2^21379944 is an apocalyptic number.

21379944 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21379944 is an abundant number, since it is smaller than the sum of its proper divisors (33315576).

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

21379944 is a wasteful number, since it uses less digits than its factorization.

21379944 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20769 (or 20765 counting only the distinct ones).

The product of its digits is 54432, while the sum is 39.

The square root of 21379944 is about 4623.8451531166. The cubic root of 21379944 is about 277.5463505078.

The spelling of 21379944 in words is "twenty-one million, three hundred seventy-nine thousand, nine hundred forty-four".