665607613723 has 4 divisors (see below), whose sum is σ = 716808199408. Its totient is φ = 614407028040.

The previous prime is 665607613717. The next prime is 665607613739. The reversal of 665607613723 is 327316706566.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 327316706566 = 2 ⋅163658353283.

It is not a de Polignac number, because 665607613723 - 2²⁹ = 665070742811 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665607613703) 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, 25600292823 + ... + 25600292848.

It is an arithmetic number, because the mean of its divisors is an integer number (179202049852).

Almost surely, 2^665607613723 is an apocalyptic number.

665607613723 is a deficient number, since it is larger than the sum of its proper divisors (51200585685).

665607613723 is a wasteful number, since it uses less digits than its factorization.

665607613723 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51200585684.

The product of its (nonzero) digits is 5715360, while the sum is 52.

The spelling of 665607613723 in words is "six hundred sixty-five billion, six hundred seven million, six hundred thirteen thousand, seven hundred twenty-three".