665605115506 has 4 divisors (see below), whose sum is σ = 998407673262. Its totient is φ = 332802557752.

The previous prime is 665605115489. The next prime is 665605115521. The reversal of 665605115506 is 605511506566.

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

It can be written as a sum of positive squares in only one way, i.e., 664526584225 + 1078531281 = 815185^2 + 32841^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 166401278875 + ... + 166401278878.

Almost surely, 2^665605115506 is an apocalyptic number.

665605115506 is a deficient number, since it is larger than the sum of its proper divisors (332802557756).

665605115506 is a wasteful number, since it uses less digits than its factorization.

665605115506 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 332802557755.

The product of its (nonzero) digits is 810000, while the sum is 46.

The spelling of 665605115506 in words is "six hundred sixty-five billion, six hundred five million, one hundred fifteen thousand, five hundred six".