1513317721 has 2 divisors, whose sum is σ = 1513317722. Its totient is φ = 1513317720.

The previous prime is 1513317691. The next prime is 1513317737. The reversal of 1513317721 is 1277133151.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1079845321 + 433472400 = 32861^2 + 20820^2 .

It is a cyclic number.

It is not a de Polignac number, because 1513317721 - 2⁹ = 1513317209 is a prime.

It is not a weakly prime, because it can be changed into another prime (1513311721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 756658860 + 756658861.

It is an arithmetic number, because the mean of its divisors is an integer number (756658861).

Almost surely, 2^1513317721 is an apocalyptic number.

It is an amenable number.

1513317721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1513317721 is an equidigital number, since it uses as much as digits as its factorization.

1513317721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4410, while the sum is 31.

The square root of 1513317721 is about 38901.3845640486. The cubic root of 1513317721 is about 1148.0920400433.

The spelling of 1513317721 in words is "one billion, five hundred thirteen million, three hundred seventeen thousand, seven hundred twenty-one".