857488991 has 4 divisors (see below), whose sum is σ = 858405072. Its totient is φ = 856572912.

The previous prime is 857488987. The next prime is 857488999. The reversal of 857488991 is 199884758.

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

It is a cyclic number.

It is not a de Polignac number, because 857488991 - 2² = 857488987 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 857488991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (857488999) 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, 456635 + ... + 458508.

It is an arithmetic number, because the mean of its divisors is an integer number (214601268).

Almost surely, 2^857488991 is an apocalyptic number.

857488991 is a deficient number, since it is larger than the sum of its proper divisors (916081).

857488991 is an equidigital number, since it uses as much as digits as its factorization.

857488991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 916080.

The product of its digits is 5806080, while the sum is 59.

The square root of 857488991 is about 29282.9129527785. The cubic root of 857488991 is about 950.0421000733.

The spelling of 857488991 in words is "eight hundred fifty-seven million, four hundred eighty-eight thousand, nine hundred ninety-one".