665139855869 has 16 divisors (see below), whose sum is σ = 682486871040. Its totient is φ = 647928282240.

The previous prime is 665139855859. The next prime is 665139855881. The reversal of 665139855869 is 968558931566.

It is a cyclic number.

It is not a de Polignac number, because 665139855869 - 2³² = 660844888573 is a prime.

It is a super-2 number, since 2×665139855869² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665139855839) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 30005612 + ... + 30027770.

It is an arithmetic number, because the mean of its divisors is an integer number (42655429440).

Almost surely, 2^665139855869 is an apocalyptic number.

It is an amenable number.

665139855869 is a deficient number, since it is larger than the sum of its proper divisors (17347015171).

665139855869 is a wasteful number, since it uses less digits than its factorization.

665139855869 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25180.

The product of its digits is 419904000, while the sum is 71.

The spelling of 665139855869 in words is "six hundred sixty-five billion, one hundred thirty-nine million, eight hundred fifty-five thousand, eight hundred sixty-nine".