857642647 has 4 divisors (see below), whose sum is σ = 880822216. Its totient is φ = 834463080.

The previous prime is 857642641. The next prime is 857642651. The reversal of 857642647 is 746246758.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-857642647 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 857642647.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (857642641) 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 in 3 ways as a sum of consecutive naturals, for example, 11589729 + ... + 11589802.

It is an arithmetic number, because the mean of its divisors is an integer number (220205554).

Almost surely, 2^857642647 is an apocalyptic number.

857642647 is a deficient number, since it is larger than the sum of its proper divisors (23179569).

857642647 is a wasteful number, since it uses less digits than its factorization.

857642647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23179568.

The product of its digits is 2257920, while the sum is 49.

The square root of 857642647 is about 29285.5364813418. The cubic root of 857642647 is about 950.0988436396.

The spelling of 857642647 in words is "eight hundred fifty-seven million, six hundred forty-two thousand, six hundred forty-seven".