21372937 has 2 divisors, whose sum is σ = 21372938. Its totient is φ = 21372936.

The previous prime is 21372889. The next prime is 21372977. The reversal of 21372937 is 73927312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15713296 + 5659641 = 3964^2 + 2379^2 .

It is a cyclic number.

It is not a de Polignac number, because 21372937 - 2¹¹ = 21370889 is a prime.

It is not a weakly prime, because it can be changed into another prime (21372977) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10686468 + 10686469.

It is an arithmetic number, because the mean of its divisors is an integer number (10686469).

Almost surely, 2^21372937 is an apocalyptic number.

It is an amenable number.

21372937 is a deficient number, since it is larger than the sum of its proper divisors (1).

21372937 is an equidigital number, since it uses as much as digits as its factorization.

21372937 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15876, while the sum is 34.

The square root of 21372937 is about 4623.0873883153. The cubic root of 21372937 is about 277.5160264531.

The spelling of 21372937 in words is "twenty-one million, three hundred seventy-two thousand, nine hundred thirty-seven".