21938377 has 2 divisors, whose sum is σ = 21938378. Its totient is φ = 21938376.

The previous prime is 21938353. The next prime is 21938387. The reversal of 21938377 is 77383912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18567481 + 3370896 = 4309^2 + 1836^2 .

It is a cyclic number.

It is not a de Polignac number, because 21938377 - 2⁷ = 21938249 is a prime.

It is not a weakly prime, because it can be changed into another prime (21938327) by changing a digit.

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 as a sum of consecutive naturals, namely, 10969188 + 10969189.

It is an arithmetic number, because the mean of its divisors is an integer number (10969189).

Almost surely, 2^21938377 is an apocalyptic number.

It is an amenable number.

21938377 is a deficient number, since it is larger than the sum of its proper divisors (1).

21938377 is an equidigital number, since it uses as much as digits as its factorization.

21938377 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 63504, while the sum is 40.

The square root of 21938377 is about 4683.8421194571. The cubic root of 21938377 is about 279.9420670960.

The spelling of 21938377 in words is "twenty-one million, nine hundred thirty-eight thousand, three hundred seventy-seven".