1538941681 has 2 divisors, whose sum is σ = 1538941682. Its totient is φ = 1538941680.

The previous prime is 1538941673. The next prime is 1538941699. The reversal of 1538941681 is 1861498351.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1538600625 + 341056 = 39225^2 + 584^2 .

It is a cyclic number.

It is not a de Polignac number, because 1538941681 - 2³ = 1538941673 is a prime.

It is a super-2 number, since 2×1538941681² = 4736682995038211522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1538941381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 769470840 + 769470841.

It is an arithmetic number, because the mean of its divisors is an integer number (769470841).

Almost surely, 2^1538941681 is an apocalyptic number.

It is an amenable number.

1538941681 is a deficient number, since it is larger than the sum of its proper divisors (1).

1538941681 is an equidigital number, since it uses as much as digits as its factorization.

1538941681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 207360, while the sum is 46.

The square root of 1538941681 is about 39229.3471905919. The cubic root of 1538941681 is about 1154.5357556551.

The spelling of 1538941681 in words is "one billion, five hundred thirty-eight million, nine hundred forty-one thousand, six hundred eighty-one".