21596491 has 8 divisors (see below), whose sum is σ = 25478144. Its totient is φ = 17913960.

The previous prime is 21596489. The next prime is 21596513. The reversal of 21596491 is 19469512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21596491 - 2¹ = 21596489 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21596491.

It is not an unprimeable number, because it can be changed into a prime (21596401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49545 + ... + 49978.

It is an arithmetic number, because the mean of its divisors is an integer number (3184768).

Almost surely, 2^21596491 is an apocalyptic number.

21596491 is a deficient number, since it is larger than the sum of its proper divisors (3881653).

21596491 is an equidigital number, since it uses as much as digits as its factorization.

21596491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99561.

The product of its digits is 19440, while the sum is 37.

The square root of 21596491 is about 4647.2024918224. The cubic root of 21596491 is about 278.4802483341.

The spelling of 21596491 in words is "twenty-one million, five hundred ninety-six thousand, four hundred ninety-one".