665305521242523 has 24 divisors (see below), whose sum is σ = 1092602584709712. Its totient is φ = 357811372767744.

The previous prime is 665305521242459. The next prime is 665305521242533. The reversal of 665305521242523 is 325242125503566.

It is not a de Polignac number, because 665305521242523 - 2⁶ = 665305521242459 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is not an unprimeable number, because it can be changed into a prime (665305521242533) 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 23 ways as a sum of consecutive naturals, for example, 133114347490 + ... + 133114352487.

It is an arithmetic number, because the mean of its divisors is an integer number (45525107696238).

Almost surely, 2^{665305521242523} is an apocalyptic number.

665305521242523 is a deficient number, since it is larger than the sum of its proper divisors (427297063467189).

665305521242523 is a wasteful number, since it uses less digits than its factorization.

665305521242523 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 266228700011 (or 266228700004 counting only the distinct ones).

The product of its (nonzero) digits is 12960000, while the sum is 51.

The spelling of 665305521242523 in words is "six hundred sixty-five trillion, three hundred five billion, five hundred twenty-one million, two hundred forty-two thousand, five hundred twenty-three".