857489639 has 4 divisors (see below), whose sum is σ = 907930224. Its totient is φ = 807049056.

The previous prime is 857489587. The next prime is 857489641. The reversal of 857489639 is 936984758.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 936984758 = 2 ⋅468492379.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-857489639 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (857489239) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25220267 + ... + 25220300.

It is an arithmetic number, because the mean of its divisors is an integer number (226982556).

Almost surely, 2^857489639 is an apocalyptic number.

857489639 is a deficient number, since it is larger than the sum of its proper divisors (50440585).

857489639 is a wasteful number, since it uses less digits than its factorization.

857489639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50440584.

The product of its digits is 13063680, while the sum is 59.

The square root of 857489639 is about 29282.9240172494. The cubic root of 857489639 is about 950.0423393872.

The spelling of 857489639 in words is "eight hundred fifty-seven million, four hundred eighty-nine thousand, six hundred thirty-nine".