21938867 has 2 divisors, whose sum is σ = 21938868. Its totient is φ = 21938866.

The previous prime is 21938843. The next prime is 21938881. The reversal of 21938867 is 76883912.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21938867 - 2¹⁰ = 21937843 is a prime.

It is not a weakly prime, because it can be changed into another prime (21938167) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10969433 + 10969434.

It is an arithmetic number, because the mean of its divisors is an integer number (10969434).

Almost surely, 2^21938867 is an apocalyptic number.

21938867 is a deficient number, since it is larger than the sum of its proper divisors (1).

21938867 is an equidigital number, since it uses as much as digits as its factorization.

21938867 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 145152, while the sum is 44.

The square root of 21938867 is about 4683.8944266497. The cubic root of 21938867 is about 279.9441512761.

The spelling of 21938867 in words is "twenty-one million, nine hundred thirty-eight thousand, eight hundred sixty-seven".