20640994 has 16 divisors (see below), whose sum is σ = 34107840. Its totient is φ = 9290160.

The previous prime is 20640967. The next prime is 20641001. The reversal of 20640994 is 49904602.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2289 + ... + 6820.

It is an arithmetic number, because the mean of its divisors is an integer number (2131740).

Almost surely, 2^20640994 is an apocalyptic number.

20640994 is a deficient number, since it is larger than the sum of its proper divisors (13466846).

20640994 is a wasteful number, since it uses less digits than its factorization.

20640994 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9225.

The product of its (nonzero) digits is 15552, while the sum is 34.

The square root of 20640994 is about 4543.2360713483. The cubic root of 20640994 is about 274.3111973833.

The spelling of 20640994 in words is "twenty million, six hundred forty thousand, nine hundred ninety-four".