20856879 has 8 divisors (see below), whose sum is σ = 30899120. Its totient is φ = 13904568.

The previous prime is 20856877. The next prime is 20856881. The reversal of 20856879 is 97865802.

It is an interprime number because it is at equal distance from previous prime (20856877) and next prime (20856881).

It is not a de Polignac number, because 20856879 - 2¹ = 20856877 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20856877) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 386212 + ... + 386265.

It is an arithmetic number, because the mean of its divisors is an integer number (3862390).

Almost surely, 2^20856879 is an apocalyptic number.

20856879 is a deficient number, since it is larger than the sum of its proper divisors (10042241).

20856879 is an equidigital number, since it uses as much as digits as its factorization.

20856879 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 772486 (or 772480 counting only the distinct ones).

The product of its (nonzero) digits is 241920, while the sum is 45.

The square root of 20856879 is about 4566.9332160652. The cubic root of 20856879 is about 275.2642264844.

The spelling of 20856879 in words is "twenty million, eight hundred fifty-six thousand, eight hundred seventy-nine".