669131257 has 4 divisors (see below), whose sum is σ = 670878720. Its totient is φ = 667383796.

The previous prime is 669131207. The next prime is 669131269. The reversal of 669131257 is 752131966.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 752131966 = 2 ⋅376065983.

It is a cyclic number.

It is not a de Polignac number, because 669131257 - 2⁷ = 669131129 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (669131207) 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, 873157 + ... + 873922.

It is an arithmetic number, because the mean of its divisors is an integer number (167719680).

Almost surely, 2^669131257 is an apocalyptic number.

It is an amenable number.

669131257 is a deficient number, since it is larger than the sum of its proper divisors (1747463).

669131257 is a wasteful number, since it uses less digits than its factorization.

669131257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1747462.

The product of its digits is 68040, while the sum is 40.

The square root of 669131257 is about 25867.5715327125. The cubic root of 669131257 is about 874.6556498617.

The spelling of 669131257 in words is "six hundred sixty-nine million, one hundred thirty-one thousand, two hundred fifty-seven".