857640851 has 2 divisors, whose sum is σ = 857640852. Its totient is φ = 857640850.

The previous prime is 857640841. The next prime is 857640853. The reversal of 857640851 is 158046758.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-857640851 is a prime.

It is a Sophie Germain prime.

Together with 857640853, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (857640853) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 428820425 + 428820426.

It is an arithmetic number, because the mean of its divisors is an integer number (428820426).

Almost surely, 2^857640851 is an apocalyptic number.

857640851 is a deficient number, since it is larger than the sum of its proper divisors (1).

857640851 is an equidigital number, since it uses as much as digits as its factorization.

857640851 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 268800, while the sum is 44.

The square root of 857640851 is about 29285.5058177249. The cubic root of 857640851 is about 950.0981804346.

The spelling of 857640851 in words is "eight hundred fifty-seven million, six hundred forty thousand, eight hundred fifty-one".