666131331 has 4 divisors (see below), whose sum is σ = 888175112. Its totient is φ = 444087552.

The previous prime is 666131327. The next prime is 666131369. The reversal of 666131331 is 133131666.

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

It is not a de Polignac number, because 666131331 - 2² = 666131327 is a prime.

It is a super-2 number, since 2×666131331² = 887461900279663122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666131381) 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, 111021886 + ... + 111021891.

It is an arithmetic number, because the mean of its divisors is an integer number (222043778).

Almost surely, 2^666131331 is an apocalyptic number.

666131331 is a deficient number, since it is larger than the sum of its proper divisors (222043781).

666131331 is a wasteful number, since it uses less digits than its factorization.

666131331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 222043780.

The product of its digits is 5832, while the sum is 30.

The square root of 666131331 is about 25809.5201621417. The cubic root of 666131331 is about 873.3465727295.

Adding to 666131331 its reverse (133131666), we get a palindrome (799262997).

The spelling of 666131331 in words is "six hundred sixty-six million, one hundred thirty-one thousand, three hundred thirty-one".