665122993721 has 8 divisors (see below), whose sum is σ = 667696106880. Its totient is φ = 662550215392.

The previous prime is 665122993649. The next prime is 665122993739. The reversal of 665122993721 is 127399221566.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 665122993721 - 2²² = 665118799417 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665122993421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4349285 + ... + 4499613.

It is an arithmetic number, because the mean of its divisors is an integer number (83462013360).

Almost surely, 2^665122993721 is an apocalyptic number.

It is an amenable number.

665122993721 is a deficient number, since it is larger than the sum of its proper divisors (2573113159).

665122993721 is a wasteful number, since it uses less digits than its factorization.

665122993721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 167415.

The product of its digits is 2449440, while the sum is 53.

The spelling of 665122993721 in words is "six hundred sixty-five billion, one hundred twenty-two million, nine hundred ninety-three thousand, seven hundred twenty-one".