15781138129 has 9 divisors (see below), whose sum is σ = 15874013467. Its totient is φ = 15688805224.

The previous prime is 15781138127. The next prime is 15781138147. The reversal of 15781138129 is 92183118751.

The square root of 15781138129 is 125623.

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., 1038321729 + 14742816400 = 32223^2 + 121420^2 .

It is not a de Polignac number, because 15781138129 - 2¹ = 15781138127 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15781138127) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 33792354 + ... + 33792820.

Almost surely, 2^15781138129 is an apocalyptic number.

15781138129 is the 125623-rd square number.

15781138129 is the 62812-nd centered octagonal number.

It is an amenable number.

15781138129 is a deficient number, since it is larger than the sum of its proper divisors (92875338).

15781138129 is an frugal number, since it uses more digits than its factorization.

15781138129 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1472 (or 736 counting only the distinct ones).

The product of its digits is 120960, while the sum is 46.

The spelling of 15781138129 in words is "fifteen billion, seven hundred eighty-one million, one hundred thirty-eight thousand, one hundred twenty-nine".