20640595 has 4 divisors (see below), whose sum is σ = 24768720. Its totient is φ = 16512472.

The previous prime is 20640583. The next prime is 20640617. The reversal of 20640595 is 59504602.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20640595 - 2⁵ = 20640563 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2064055 + ... + 2064064.

It is an arithmetic number, because the mean of its divisors is an integer number (6192180).

Almost surely, 2^20640595 is an apocalyptic number.

20640595 is a deficient number, since it is larger than the sum of its proper divisors (4128125).

20640595 is an equidigital number, since it uses as much as digits as its factorization.

20640595 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4128124.

The product of its (nonzero) digits is 10800, while the sum is 31.

The square root of 20640595 is about 4543.1921597045. The cubic root of 20640595 is about 274.3094298510.

The spelling of 20640595 in words is "twenty million, six hundred forty thousand, five hundred ninety-five".