1516245721 has 9 divisors (see below), whose sum is σ = 1585972479. Its totient is φ = 1449465336.

The previous prime is 1516245701. The next prime is 1516245727. The reversal of 1516245721 is 1275426151.

The square root of 1516245721 is 38939.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 577681225 + 938564496 = 24035^2 + 30636^2 .

It is not a de Polignac number, because 1516245721 - 2¹⁵ = 1516212953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1516245727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 894751 + ... + 896443.

Almost surely, 2^1516245721 is an apocalyptic number.

1516245721 is the 38939-th square number.

1516245721 is the 19470-th centered octagonal number.

It is an amenable number.

1516245721 is a deficient number, since it is larger than the sum of its proper divisors (69726758).

1516245721 is an frugal number, since it uses more digits than its factorization.

1516245721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3432 (or 1716 counting only the distinct ones).

The product of its digits is 16800, while the sum is 34.

The cubic root of 1516245721 is about 1148.8320141486.

The spelling of 1516245721 in words is "one billion, five hundred sixteen million, two hundred forty-five thousand, seven hundred twenty-one".