1513072721 has 2 divisors, whose sum is σ = 1513072722. Its totient is φ = 1513072720.

The previous prime is 1513072703. The next prime is 1513072723. The reversal of 1513072721 is 1272703151.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1444000000 + 69072721 = 38000^2 + 8311^2 .

It is a cyclic number.

It is not a de Polignac number, because 1513072721 - 2³⁰ = 439330897 is a prime.

Together with 1513072723, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1513072723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 756536360 + 756536361.

It is an arithmetic number, because the mean of its divisors is an integer number (756536361).

Almost surely, 2^1513072721 is an apocalyptic number.

It is an amenable number.

1513072721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1513072721 is an equidigital number, since it uses as much as digits as its factorization.

1513072721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2940, while the sum is 29.

The square root of 1513072721 is about 38898.2354484108. The cubic root of 1513072721 is about 1148.0300795515.

Adding to 1513072721 its reverse (1272703151), we get a palindrome (2785775872).

The spelling of 1513072721 in words is "one billion, five hundred thirteen million, seventy-two thousand, seven hundred twenty-one".