21937379 has 2 divisors, whose sum is σ = 21937380. Its totient is φ = 21937378.

The previous prime is 21937373. The next prime is 21937387. The reversal of 21937379 is 97373912.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21937379 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (21937373) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10968689 + 10968690.

It is an arithmetic number, because the mean of its divisors is an integer number (10968690).

Almost surely, 2^21937379 is an apocalyptic number.

21937379 is a deficient number, since it is larger than the sum of its proper divisors (1).

21937379 is an equidigital number, since it uses as much as digits as its factorization.

21937379 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 71442, while the sum is 41.

The square root of 21937379 is about 4683.7355817766. The cubic root of 21937379 is about 279.9378220779.

The spelling of 21937379 in words is "twenty-one million, nine hundred thirty-seven thousand, three hundred seventy-nine".