18077609209 has 27 divisors (see below), whose sum is σ = 21137432911. Its totient is φ = 15445960640.

The previous prime is 18077609191. The next prime is 18077609213. The reversal of 18077609209 is 90290677081.

It is a happy number.

The square root of 18077609209 is 134453.

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., 14074263225 + 4003345984 = 118635^2 + 63272^2 .

It is not a de Polignac number, because 18077609209 - 2¹¹ = 18077607161 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18077609009) 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, 25142352 + ... + 25143070.

Almost surely, 2^18077609209 is an apocalyptic number.

18077609209 is the 134453-rd square number.

18077609209 is the 67227-th centered octagonal number.

It is an amenable number.

18077609209 is a deficient number, since it is larger than the sum of its proper divisors (3059823702).

18077609209 is an frugal number, since it uses more digits than its factorization.

18077609209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1494 (or 747 counting only the distinct ones).

The product of its (nonzero) digits is 381024, while the sum is 49.

Multiplying 18077609209 by its sum of digits (49), we get a square (885802851241 = 941171²).

The spelling of 18077609209 in words is "eighteen billion, seventy-seven million, six hundred nine thousand, two hundred nine".