661245317 has 2 divisors, whose sum is σ = 661245318. Its totient is φ = 661245316.

The previous prime is 661245301. The next prime is 661245329. The reversal of 661245317 is 713542166.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 346927876 + 314317441 = 18626^2 + 17729^2 .

It is a cyclic number.

It is not a de Polignac number, because 661245317 - 2⁴ = 661245301 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661245337) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330622658 + 330622659.

It is an arithmetic number, because the mean of its divisors is an integer number (330622659).

Almost surely, 2^661245317 is an apocalyptic number.

It is an amenable number.

661245317 is a deficient number, since it is larger than the sum of its proper divisors (1).

661245317 is an equidigital number, since it uses as much as digits as its factorization.

661245317 is an evil number, because the sum of its binary digits is even.

The product of its digits is 30240, while the sum is 35.

The square root of 661245317 is about 25714.6906845095. The cubic root of 661245317 is about 871.2060241405.

The spelling of 661245317 in words is "six hundred sixty-one million, two hundred forty-five thousand, three hundred seventeen".