21674591 has 2 divisors, whose sum is σ = 21674592. Its totient is φ = 21674590.

The previous prime is 21674561. The next prime is 21674617. The reversal of 21674591 is 19547612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21674591 - 2¹⁴ = 21658207 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21674501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10837295 + 10837296.

It is an arithmetic number, because the mean of its divisors is an integer number (10837296).

Almost surely, 2^21674591 is an apocalyptic number.

21674591 is a deficient number, since it is larger than the sum of its proper divisors (1).

21674591 is an equidigital number, since it uses as much as digits as its factorization.

21674591 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15120, while the sum is 35.

The square root of 21674591 is about 4655.5978133855. The cubic root of 21674591 is about 278.8155364819.

The spelling of 21674591 in words is "twenty-one million, six hundred seventy-four thousand, five hundred ninety-one".