666879731 has 4 divisors (see below), whose sum is σ = 762148272. Its totient is φ = 571611192.

The previous prime is 666879713. The next prime is 666879809. The reversal of 666879731 is 137978666.

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 666879731 - 2¹⁴ = 666863347 is a prime.

It is a super-2 number, since 2×666879731² = 889457151237264722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666879431) 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, 47634260 + ... + 47634273.

It is an arithmetic number, because the mean of its divisors is an integer number (190537068).

Almost surely, 2^666879731 is an apocalyptic number.

666879731 is a deficient number, since it is larger than the sum of its proper divisors (95268541).

666879731 is an equidigital number, since it uses as much as digits as its factorization.

666879731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95268540.

The product of its digits is 2286144, while the sum is 53.

The square root of 666879731 is about 25824.0146181805. The cubic root of 666879731 is about 873.6735192434.

The spelling of 666879731 in words is "six hundred sixty-six million, eight hundred seventy-nine thousand, seven hundred thirty-one".