138051631809 has 81 divisors (see below), whose sum is σ = 251364975849. Its totient is φ = 72764939520.

The previous prime is 138051631801. The next prime is 138051631819. The reversal of 138051631809 is 908136150831.

It is a happy number.

The square root of 138051631809 is 371553.

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

138051631809 is a `hidden beast` number, since 1 + 3 + 8 + 0 + 5 + 1 + 631 + 8 + 0 + 9 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 64300280625 + 73751351184 = 253575^2 + 271572^2 .

It is not a de Polignac number, because 138051631809 - 2³ = 138051631801 is a prime.

It is a super-2 number, since 2×138051631809² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (138051631801) 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 80 ways as a sum of consecutive naturals, for example, 101433289 + ... + 101434649.

Almost surely, 2^138051631809 is an apocalyptic number.

138051631809 is the 371553-rd square number.

138051631809 is the 185777-th centered octagonal number.

It is an amenable number.

138051631809 is a deficient number, since it is larger than the sum of its proper divisors (113313344040).

138051631809 is an equidigital number, since it uses as much as digits as its factorization.

138051631809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2768 (or 1384 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 45.

The spelling of 138051631809 in words is "one hundred thirty-eight billion, fifty-one million, six hundred thirty-one thousand, eight hundred nine".