660634518641 has 4 divisors (see below), whose sum is σ = 664687491312. Its totient is φ = 656581545972.

The previous prime is 660634518623. The next prime is 660634518757. The reversal of 660634518641 is 146815436066.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a de Polignac number, because none of the positive numbers 2^k-660634518641 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 660634518641.

It is not an unprimeable number, because it can be changed into a prime (660634518611) 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, 2026486091 + ... + 2026486416.

It is an arithmetic number, because the mean of its divisors is an integer number (166171872828).

Almost surely, 2^660634518641 is an apocalyptic number.

It is an amenable number.

660634518641 is a deficient number, since it is larger than the sum of its proper divisors (4052972671).

660634518641 is a wasteful number, since it uses less digits than its factorization.

660634518641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4052972670.

The product of its (nonzero) digits is 2488320, while the sum is 50.

The spelling of 660634518641 in words is "six hundred sixty billion, six hundred thirty-four million, five hundred eighteen thousand, six hundred forty-one".