18279851209 has 9 divisors (see below), whose sum is σ = 18638568039. Its totient is φ = 17927917800.

The previous prime is 18279851207. The next prime is 18279851257. The reversal of 18279851209 is 90215897281.

The square root of 18279851209 is 135203.

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., 13177892025 + 5101959184 = 114795^2 + 71428^2 .

It is not a de Polignac number, because 18279851209 - 2¹ = 18279851207 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18279851207) 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, 7164484 + ... + 7167034.

Almost surely, 2^18279851209 is an apocalyptic number.

18279851209 is the 135203-rd square number.

18279851209 is the 67602-nd centered octagonal number.

It is an amenable number.

18279851209 is a deficient number, since it is larger than the sum of its proper divisors (358716830).

18279851209 is an frugal number, since it uses more digits than its factorization.

18279851209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5208 (or 2604 counting only the distinct ones).

The product of its (nonzero) digits is 725760, while the sum is 52.

The spelling of 18279851209 in words is "eighteen billion, two hundred seventy-nine million, eight hundred fifty-one thousand, two hundred nine".