660860491 has 2 divisors, whose sum is σ = 660860492. Its totient is φ = 660860490.

The previous prime is 660860477. The next prime is 660860513. The reversal of 660860491 is 194068066.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 660860491 - 2²⁷ = 526642763 is a prime.

It is a super-2 number, since 2×660860491² = 873473177129522162, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (660860411) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330430245 + 330430246.

It is an arithmetic number, because the mean of its divisors is an integer number (330430246).

Almost surely, 2^660860491 is an apocalyptic number.

660860491 is a deficient number, since it is larger than the sum of its proper divisors (1).

660860491 is an equidigital number, since it uses as much as digits as its factorization.

660860491 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 62208, while the sum is 40.

The square root of 660860491 is about 25707.2069855906. The cubic root of 660860491 is about 871.0369856210.

The spelling of 660860491 in words is "six hundred sixty million, eight hundred sixty thousand, four hundred ninety-one".