661739521317 has 8 divisors (see below), whose sum is σ = 1008364984896. Its totient is φ = 378136869312.

The previous prime is 661739521297. The next prime is 661739521327. The reversal of 661739521317 is 713125937166.

It is a happy number.

661739521317 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 661739521317 - 2¹⁶ = 661739455781 is a prime.

It is a Smith number, since the sum of its digits (51) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 661739521317.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661739521327) 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, 15755702868 + ... + 15755702909.

It is an arithmetic number, because the mean of its divisors is an integer number (126045623112).

Almost surely, 2^661739521317 is an apocalyptic number.

It is an amenable number.

661739521317 is a deficient number, since it is larger than the sum of its proper divisors (346625463579).

661739521317 is a wasteful number, since it uses less digits than its factorization.

661739521317 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31511405787.

The product of its digits is 1428840, while the sum is 51.

The spelling of 661739521317 in words is "six hundred sixty-one billion, seven hundred thirty-nine million, five hundred twenty-one thousand, three hundred seventeen".