617721317 has 8 divisors (see below), whose sum is σ = 626837400. Its totient is φ = 608661504.

The previous prime is 617721287. The next prime is 617721323. The reversal of 617721317 is 713127716.

It is a Cunningham number, because it is equal to 24854²+1.

It can be written as a sum of positive squares in 4 ways, for example, as 277355716 + 340365601 = 16654^2 + 18449^2 .

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 617721317 - 2²⁰ = 616672741 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (617721347) 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, 8309 + ... + 36117.

It is an arithmetic number, because the mean of its divisors is an integer number (78354675).

Almost surely, 2^617721317 is an apocalyptic number.

It is an amenable number.

617721317 is a deficient number, since it is larger than the sum of its proper divisors (9116083).

617721317 is a wasteful number, since it uses less digits than its factorization.

617721317 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28135.

The product of its digits is 12348, while the sum is 35.

The square root of 617721317 is about 24854.0000201175. Note that the first 4 decimals coincide. The cubic root of 617721317 is about 851.6559721970.

The spelling of 617721317 in words is "six hundred seventeen million, seven hundred twenty-one thousand, three hundred seventeen".