21974951 has 2 divisors, whose sum is σ = 21974952. Its totient is φ = 21974950.

The previous prime is 21974941. The next prime is 21974957. The reversal of 21974951 is 15947912.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21974951 - 2²² = 17780647 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21974957) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10987475 + 10987476.

It is an arithmetic number, because the mean of its divisors is an integer number (10987476).

Almost surely, 2^21974951 is an apocalyptic number.

21974951 is a deficient number, since it is larger than the sum of its proper divisors (1).

21974951 is an equidigital number, since it uses as much as digits as its factorization.

21974951 is an evil number, because the sum of its binary digits is even.

The product of its digits is 22680, while the sum is 38.

The square root of 21974951 is about 4687.7447669428. The cubic root of 21974951 is about 280.0975467949.

The spelling of 21974951 in words is "twenty-one million, nine hundred seventy-four thousand, nine hundred fifty-one".