1539306721 has 2 divisors, whose sum is σ = 1539306722. Its totient is φ = 1539306720.

The previous prime is 1539306653. The next prime is 1539306737. The reversal of 1539306721 is 1276039351.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1121513121 + 417793600 = 33489^2 + 20440^2 .

It is a cyclic number.

It is not a de Polignac number, because 1539306721 - 2²⁵ = 1505752289 is a prime.

It is not a weakly prime, because it can be changed into another prime (1539306781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 769653360 + 769653361.

It is an arithmetic number, because the mean of its divisors is an integer number (769653361).

Almost surely, 2^1539306721 is an apocalyptic number.

It is an amenable number.

1539306721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1539306721 is an equidigital number, since it uses as much as digits as its factorization.

1539306721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 34020, while the sum is 37.

The square root of 1539306721 is about 39233.9995539583. Note that the first 3 decimals coincide. The cubic root of 1539306721 is about 1154.6270344906.

The spelling of 1539306721 in words is "one billion, five hundred thirty-nine million, three hundred six thousand, seven hundred twenty-one".