21974369 has 2 divisors, whose sum is σ = 21974370. Its totient is φ = 21974368.

The previous prime is 21974357. The next prime is 21974413. The reversal of 21974369 is 96347912.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21967969 + 6400 = 4687^2 + 80^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21974369 is a prime.

It is a super-2 number, since 2×21974369² = 965745785896322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21970369) 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, 10987184 + 10987185.

It is an arithmetic number, because the mean of its divisors is an integer number (10987185).

Almost surely, 2^21974369 is an apocalyptic number.

It is an amenable number.

21974369 is a deficient number, since it is larger than the sum of its proper divisors (1).

21974369 is an equidigital number, since it uses as much as digits as its factorization.

21974369 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 81648, while the sum is 41.

The square root of 21974369 is about 4687.6826897733. The cubic root of 21974369 is about 280.0950740065.

The spelling of 21974369 in words is "twenty-one million, nine hundred seventy-four thousand, three hundred sixty-nine".