20640524 has 24 divisors (see below), whose sum is σ = 37537920. Its totient is φ = 9922176.

The previous prime is 20640511. The next prime is 20640541. The reversal of 20640524 is 42504602.

It is a self number, because there is not a number n which added to its sum of digits gives 20640524.

It is an unprimeable number.

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 in 7 ways as a sum of consecutive naturals, for example, 12389 + ... + 13955.

It is an arithmetic number, because the mean of its divisors is an integer number (1564080).

Almost surely, 2^20640524 is an apocalyptic number.

It is an amenable number.

20640524 is a deficient number, since it is larger than the sum of its proper divisors (16897396).

20640524 is a wasteful number, since it uses less digits than its factorization.

20640524 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1697 (or 1695 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 23.

The square root of 20640524 is about 4543.1843458086. The cubic root of 20640524 is about 274.3091153253.

The spelling of 20640524 in words is "twenty million, six hundred forty thousand, five hundred twenty-four".