21598091 has 2 divisors, whose sum is σ = 21598092. Its totient is φ = 21598090.

The previous prime is 21598061. The next prime is 21598111. The reversal of 21598091 is 19089512.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21598091 - 2¹⁰ = 21597067 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21598061) 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, 10799045 + 10799046.

It is an arithmetic number, because the mean of its divisors is an integer number (10799046).

Almost surely, 2^21598091 is an apocalyptic number.

21598091 is a deficient number, since it is larger than the sum of its proper divisors (1).

21598091 is an equidigital number, since it uses as much as digits as its factorization.

21598091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6480, while the sum is 35.

The square root of 21598091 is about 4647.3746352107. The cubic root of 21598091 is about 278.4871253370.

The spelling of 21598091 in words is "twenty-one million, five hundred ninety-eight thousand, ninety-one".