18378789128401 has 9 divisors (see below), whose sum is σ = 19901352718449. Its totient is φ = 16964984673936.

The previous prime is 18378789128383. The next prime is 18378789128471. The reversal of 18378789128401 is 10482198787381.

The square root of 18378789128401 is 4287049.

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

It can be written as a sum of positive squares in 4 ways, for example, as 1236208198801 + 17142580929600 = 1111849^2 + 4140360^2 .

It is not a de Polignac number, because 18378789128401 - 2⁵ = 18378789128369 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18378789128471) by changing a digit.

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, 55566751 + ... + 55896523.

It is an arithmetic number, because the mean of its divisors is an integer number (2211261413161).

Almost surely, 2^{18378789128401} is an apocalyptic number.

18378789128401 is the 4287049-th square number.

18378789128401 is the 2143525-th centered octagonal number.

It is an amenable number.

18378789128401 is a deficient number, since it is larger than the sum of its proper divisors (1522563590048).

18378789128401 is an frugal number, since it uses more digits than its factorization.

18378789128401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 659572 (or 329786 counting only the distinct ones).

The product of its (nonzero) digits is 43352064, while the sum is 67.

The spelling of 18378789128401 in words is "eighteen trillion, three hundred seventy-eight billion, seven hundred eighty-nine million, one hundred twenty-eight thousand, four hundred one".