1538723909 has 2 divisors, whose sum is σ = 1538723910. Its totient is φ = 1538723908.

The previous prime is 1538723903. The next prime is 1538723933. The reversal of 1538723909 is 9093278351.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1003495684 + 535228225 = 31678^2 + 23135^2 .

It is a cyclic number.

It is not a de Polignac number, because 1538723909 - 2²⁴ = 1521946693 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1538723903) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 769361954 + 769361955.

It is an arithmetic number, because the mean of its divisors is an integer number (769361955).

Almost surely, 2^1538723909 is an apocalyptic number.

It is an amenable number.

1538723909 is a deficient number, since it is larger than the sum of its proper divisors (1).

1538723909 is an equidigital number, since it uses as much as digits as its factorization.

1538723909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 408240, while the sum is 47.

The square root of 1538723909 is about 39226.5714662906. The cubic root of 1538723909 is about 1154.4812945441.

The spelling of 1538723909 in words is "one billion, five hundred thirty-eight million, seven hundred twenty-three thousand, nine hundred nine".