20640650 has 24 divisors (see below), whose sum is σ = 40414080. Its totient is φ = 7821360.

The previous prime is 20640647. The next prime is 20640667. The reversal of 20640650 is 5604602.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9914 + ... + 11813.

It is an arithmetic number, because the mean of its divisors is an integer number (1683920).

Almost surely, 2^20640650 is an apocalyptic number.

20640650 is a deficient number, since it is larger than the sum of its proper divisors (19773430).

20640650 is a wasteful number, since it uses less digits than its factorization.

20640650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21758 (or 21753 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 20640650 is about 4543.1982127132. The cubic root of 20640650 is about 274.3096734971.

The spelling of 20640650 in words is "twenty million, six hundred forty thousand, six hundred fifty".