21604967 has 2 divisors, whose sum is σ = 21604968. Its totient is φ = 21604966.

The previous prime is 21604949. The next prime is 21604987. The reversal of 21604967 is 76940612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21604967 - 2¹⁴ = 21588583 is a prime.

It is a Chen prime.

It is equal to p_1365794 and since 21604967 and 1365794 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21604937) 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, 10802483 + 10802484.

It is an arithmetic number, because the mean of its divisors is an integer number (10802484).

Almost surely, 2^21604967 is an apocalyptic number.

21604967 is a deficient number, since it is larger than the sum of its proper divisors (1).

21604967 is an equidigital number, since it uses as much as digits as its factorization.

21604967 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 18144, while the sum is 35.

The square root of 21604967 is about 4648.1143488516. The cubic root of 21604967 is about 278.5166753916.

The spelling of 21604967 in words is "twenty-one million, six hundred four thousand, nine hundred sixty-seven".