856877971 has 2 divisors, whose sum is σ = 856877972. Its totient is φ = 856877970.

The previous prime is 856877969. The next prime is 856877981. The reversal of 856877971 is 179778658.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 856877971 - 2¹ = 856877969 is a prime.

Together with 856877969, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (856877981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 428438985 + 428438986.

It is an arithmetic number, because the mean of its divisors is an integer number (428438986).

Almost surely, 2^856877971 is an apocalyptic number.

856877971 is a deficient number, since it is larger than the sum of its proper divisors (1).

856877971 is an equidigital number, since it uses as much as digits as its factorization.

856877971 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5927040, while the sum is 58.

The square root of 856877971 is about 29272.4780467934. The cubic root of 856877971 is about 949.8163896306.

The spelling of 856877971 in words is "eight hundred fifty-six million, eight hundred seventy-seven thousand, nine hundred seventy-one".