491927857 has 4 divisors (see below), whose sum is σ = 494476900. Its totient is φ = 489378816.

The previous prime is 491927797. The next prime is 491927867. The reversal of 491927857 is 758729194.

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

It can be written as a sum of positive squares in 2 ways, for example, as 126697536 + 365230321 = 11256^2 + 19111^2 .

It is a cyclic number.

It is not a de Polignac number, because 491927857 - 2²³ = 483539249 is a prime.

It is a super-2 number, since 2×491927857² = 483986032985224898, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (491927867) 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, 1274232 + ... + 1274617.

It is an arithmetic number, because the mean of its divisors is an integer number (123619225).

Almost surely, 2^491927857 is an apocalyptic number.

It is an amenable number.

491927857 is a deficient number, since it is larger than the sum of its proper divisors (2549043).

491927857 is a wasteful number, since it uses less digits than its factorization.

491927857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2549042.

The product of its digits is 1270080, while the sum is 52.

The square root of 491927857 is about 22179.4467243888. The cubic root of 491927857 is about 789.4060894301.

The spelling of 491927857 in words is "four hundred ninety-one million, nine hundred twenty-seven thousand, eight hundred fifty-seven".