660721317 has 8 divisors (see below), whose sum is σ = 895404000. Its totient is φ = 433259760.

The previous prime is 660721309. The next prime is 660721339. The reversal of 660721317 is 713127066.

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

It is not a de Polignac number, because 660721317 - 2³ = 660721309 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (660721387) 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, 1805067 + ... + 1805432.

It is an arithmetic number, because the mean of its divisors is an integer number (111925500).

Almost surely, 2^660721317 is an apocalyptic number.

It is an amenable number.

660721317 is a deficient number, since it is larger than the sum of its proper divisors (234682683).

660721317 is a wasteful number, since it uses less digits than its factorization.

660721317 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3610563.

The product of its (nonzero) digits is 10584, while the sum is 33.

The square root of 660721317 is about 25704.4999367815. The cubic root of 660721317 is about 870.9758359462.

The spelling of 660721317 in words is "six hundred sixty million, seven hundred twenty-one thousand, three hundred seventeen".