660172325521 has 8 divisors (see below), whose sum is σ = 682963819200. Its totient is φ = 637382627280.

The previous prime is 660172325509. The next prime is 660172325551. The reversal of 660172325521 is 125523271066.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 660172325521 - 2²⁹ = 659635454609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (660172325551) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 321666 + ... + 1193236.

It is an arithmetic number, because the mean of its divisors is an integer number (85370477400).

Almost surely, 2^660172325521 is an apocalyptic number.

It is an amenable number.

660172325521 is a deficient number, since it is larger than the sum of its proper divisors (22791493679).

660172325521 is a wasteful number, since it uses less digits than its factorization.

660172325521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 897719.

The product of its (nonzero) digits is 151200, while the sum is 40.

Adding to 660172325521 its reverse (125523271066), we get a palindrome (785695596587).

The spelling of 660172325521 in words is "six hundred sixty billion, one hundred seventy-two million, three hundred twenty-five thousand, five hundred twenty-one".