857617021 has 4 divisors (see below), whose sum is σ = 860374944. Its totient is φ = 854859100.

The previous prime is 857617001. The next prime is 857617039. The reversal of 857617021 is 120716758.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 857617021 - 2⁵ = 857616989 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 (857617001) 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, 1378495 + ... + 1379116.

It is an arithmetic number, because the mean of its divisors is an integer number (215093736).

Almost surely, 2^857617021 is an apocalyptic number.

It is an amenable number.

857617021 is a deficient number, since it is larger than the sum of its proper divisors (2757923).

857617021 is a wasteful number, since it uses less digits than its factorization.

857617021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2757922.

The product of its (nonzero) digits is 23520, while the sum is 37.

The square root of 857617021 is about 29285.0989583440. The cubic root of 857617021 is about 950.0893806947.

The spelling of 857617021 in words is "eight hundred fifty-seven million, six hundred seventeen thousand, twenty-one".