856859881 has 2 divisors, whose sum is σ = 856859882. Its totient is φ = 856859880.

The previous prime is 856859873. The next prime is 856859893. The reversal of 856859881 is 188958658.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 821338281 + 35521600 = 28659^2 + 5960^2 .

It is a cyclic number.

It is not a de Polignac number, because 856859881 - 2³ = 856859873 is a prime.

It is a super-2 number, since 2×856859881² = 1468417711334668322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (856859281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 428429940 + 428429941.

It is an arithmetic number, because the mean of its divisors is an integer number (428429941).

Almost surely, 2^856859881 is an apocalyptic number.

It is an amenable number.

856859881 is a deficient number, since it is larger than the sum of its proper divisors (1).

856859881 is an equidigital number, since it uses as much as digits as its factorization.

856859881 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5529600, while the sum is 58.

The square root of 856859881 is about 29272.1690518485. The cubic root of 856859881 is about 949.8097055597.

The spelling of 856859881 in words is "eight hundred fifty-six million, eight hundred fifty-nine thousand, eight hundred eighty-one".