19745820915129 has 27 divisors (see below), whose sum is σ = 28717335887149. Its totient is φ = 13074217104480.

The previous prime is 19745820915127. The next prime is 19745820915157. The reversal of 19745820915129 is 92151902854791.

The square root of 19745820915129 is 4443627.

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

19745820915129 is a `hidden beast` number, since 1 + 9 + 7 + 4 + 5 + 8 + 20 + 91 + 512 + 9 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 17249294513529 + 2496526401600 = 4153227^2 + 1580040^2 .

It is not a de Polignac number, because 19745820915129 - 2¹ = 19745820915127 is a prime.

It is a super-2 number, since 2×19745820915129² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19745820915127) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 1986296299 + ... + 1986306239.

Almost surely, 2^{19745820915129} is an apocalyptic number.

19745820915129 is the 4443627-th square number.

19745820915129 is the 2221814-th centered octagonal number.

It is an amenable number.

19745820915129 is a deficient number, since it is larger than the sum of its proper divisors (8971514972020).

19745820915129 is an frugal number, since it uses more digits than its factorization.

19745820915129 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20186 (or 10093 counting only the distinct ones).

The product of its (nonzero) digits is 16329600, while the sum is 63.

The spelling of 19745820915129 in words is "nineteen trillion, seven hundred forty-five billion, eight hundred twenty million, nine hundred fifteen thousand, one hundred twenty-nine".