665131424 has 12 divisors (see below), whose sum is σ = 1309477554. Its totient is φ = 332565696.

The previous prime is 665131391. The next prime is 665131427. The reversal of 665131424 is 424131566.

It can be written as a sum of positive squares in only one way, i.e., 429815824 + 235315600 = 20732^2 + 15340^2 .

It is a super-2 number, since 2×665131424² = 884799622384535552, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (32), and also a Moran number because the ratio is a prime number: 20785357 = 665131424 / (6 + 6 + 5 + 1 + 3 + 1 + 4 + 2 + 4).

It is not an unprimeable number, because it can be changed into a prime (665131427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10392647 + ... + 10392710.

Almost surely, 2^665131424 is an apocalyptic number.

It is an amenable number.

665131424 is a deficient number, since it is larger than the sum of its proper divisors (644346130).

665131424 is a wasteful number, since it uses less digits than its factorization.

665131424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20785367 (or 20785359 counting only the distinct ones).

The product of its digits is 17280, while the sum is 32.

The square root of 665131424 is about 25790.1419926297. The cubic root of 665131424 is about 872.9093703249.

The spelling of 665131424 in words is "six hundred sixty-five million, one hundred thirty-one thousand, four hundred twenty-four".