18149208961 has 27 divisors (see below), whose sum is σ = 20204195337. Its totient is φ = 16295610240.

The previous prime is 18149208929. The next prime is 18149208971. The reversal of 18149208961 is 16980294181.

The square root of 18149208961 is 134719.

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 288490225 + 17860718736 = 16985^2 + 133644^2 .

It is not a de Polignac number, because 18149208961 - 2⁵ = 18149208929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18149208911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 75307801 + ... + 75308041.

It is an arithmetic number, because the mean of its divisors is an integer number (748303531).

Almost surely, 2^18149208961 is an apocalyptic number.

18149208961 is the 134719-th square number.

18149208961 is the 67360-th centered octagonal number.

It is an amenable number.

18149208961 is a deficient number, since it is larger than the sum of its proper divisors (2054986376).

18149208961 is an frugal number, since it uses more digits than its factorization.

18149208961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 594 (or 297 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 49.

Multiplying 18149208961 by its sum of digits (49), we get a square (889311239089 = 943033²).

The spelling of 18149208961 in words is "eighteen billion, one hundred forty-nine million, two hundred eight thousand, nine hundred sixty-one".