665135121531566 has 16 divisors (see below), whose sum is σ = 1141259798918880. Its totient is φ = 284800868725920.

The previous prime is 665135121531547. The next prime is 665135121531631.

665135121531566 is nontrivially palindromic in base 10.

It is a super-2 number, since 2×665135121531566² (a number of 30 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21420025745 + ... + 21420056796.

It is an arithmetic number, because the mean of its divisors is an integer number (71328737432430).

Almost surely, 2^{665135121531566} is an apocalyptic number.

665135121531566 is a deficient number, since it is larger than the sum of its proper divisors (476124677387314).

665135121531566 is a wasteful number, since it uses less digits than its factorization.

665135121531566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42840083659.

The product of its digits is 14580000, while the sum is 56.

The spelling of 665135121531566 in words is "six hundred sixty-five trillion, one hundred thirty-five billion, one hundred twenty-one million, five hundred thirty-one thousand, five hundred sixty-six".