20856877 has 2 divisors, whose sum is σ = 20856878. Its totient is φ = 20856876.

The previous prime is 20856839. The next prime is 20856881. The reversal of 20856877 is 77865802.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20620681 + 236196 = 4541^2 + 486^2 .

It is a cyclic number.

It is not a de Polignac number, because 20856877 - 2¹⁹ = 20332589 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20856827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10428438 + 10428439.

It is an arithmetic number, because the mean of its divisors is an integer number (10428439).

Almost surely, 2^20856877 is an apocalyptic number.

It is an amenable number.

20856877 is a deficient number, since it is larger than the sum of its proper divisors (1).

20856877 is an equidigital number, since it uses as much as digits as its factorization.

20856877 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 188160, while the sum is 43.

The square root of 20856877 is about 4566.9329970999. The cubic root of 20856877 is about 275.2642176859.

The spelling of 20856877 in words is "twenty million, eight hundred fifty-six thousand, eight hundred seventy-seven".