665128117731 has 96 divisors (see below), whose sum is σ = 1157378035968. Its totient is φ = 335828962560.

The previous prime is 665128117729. The next prime is 665128117769. The reversal of 665128117731 is 137711821566.

It is not a de Polignac number, because 665128117731 - 2¹ = 665128117729 is a prime.

It is a super-2 number, since 2×665128117731² (a number of 24 digits) contains 22 as substring.

It is a hoax number, since the sum of its digits (48) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (665128117721) 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 95 ways as a sum of consecutive naturals, for example, 9133741 + ... + 9206273.

It is an arithmetic number, because the mean of its divisors is an integer number (12056021208).

Almost surely, 2^665128117731 is an apocalyptic number.

665128117731 is a deficient number, since it is larger than the sum of its proper divisors (492249918237).

665128117731 is a wasteful number, since it uses less digits than its factorization.

665128117731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72721 (or 72714 counting only the distinct ones).

The product of its digits is 423360, while the sum is 48.

The spelling of 665128117731 in words is "six hundred sixty-five billion, one hundred twenty-eight million, one hundred seventeen thousand, seven hundred thirty-one".