20879817 has 16 divisors (see below), whose sum is σ = 32035200. Its totient is φ = 11849472.

The previous prime is 20879809. The next prime is 20879819. The reversal of 20879817 is 71897802.

It is not a de Polignac number, because 20879817 - 2³ = 20879809 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20879819) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 208 + ... + 6465.

It is an arithmetic number, because the mean of its divisors is an integer number (2002200).

Almost surely, 2^20879817 is an apocalyptic number.

It is an amenable number.

20879817 is a deficient number, since it is larger than the sum of its proper divisors (11155383).

20879817 is a wasteful number, since it uses less digits than its factorization.

20879817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6832.

The product of its (nonzero) digits is 56448, while the sum is 42.

The square root of 20879817 is about 4569.4438392435. The cubic root of 20879817 is about 275.3650996394.

The spelling of 20879817 in words is "twenty million, eight hundred seventy-nine thousand, eight hundred seventeen".