1538686431844 has 27 divisors (see below), whose sum is σ = 2733785991993. Its totient is φ = 757778612448.

The previous prime is 1538686431803. The next prime is 1538686431851. The reversal of 1538686431844 is 4481346868351.

The square root of 1538686431844 is 1240438.

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., 94574700900 + 1444111730944 = 307530^2 + 1201712^2 .

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 166214064 + ... + 166223320.

Almost surely, 2^{1538686431844} is an apocalyptic number.

1538686431844 is the 1240438-th square number.

It is an amenable number.

1538686431844 is a deficient number, since it is larger than the sum of its proper divisors (1195099560149).

1538686431844 is an frugal number, since it uses more digits than its factorization.

1538686431844 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18652 (or 9326 counting only the distinct ones).

The product of its digits is 53084160, while the sum is 61.

The spelling of 1538686431844 in words is "one trillion, five hundred thirty-eight billion, six hundred eighty-six million, four hundred thirty-one thousand, eight hundred forty-four".