20879657 has 4 divisors (see below), whose sum is σ = 20922000. Its totient is φ = 20837316.

The previous prime is 20879633. The next prime is 20879707. The reversal of 20879657 is 75697802.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20879657 - 2⁸ = 20879401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20879627) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 20423 + ... + 21420.

It is an arithmetic number, because the mean of its divisors is an integer number (5230500).

Almost surely, 2^20879657 is an apocalyptic number.

It is an amenable number.

20879657 is a deficient number, since it is larger than the sum of its proper divisors (42343).

20879657 is an equidigital number, since it uses as much as digits as its factorization.

20879657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42342.

The product of its (nonzero) digits is 211680, while the sum is 44.

The square root of 20879657 is about 4569.4263316088. The cubic root of 20879657 is about 275.3643962723.

The spelling of 20879657 in words is "twenty million, eight hundred seventy-nine thousand, six hundred fifty-seven".