18237692209 has 9 divisors (see below), whose sum is σ = 20048021931. Its totient is φ = 16578369720.

The previous prime is 18237692171. The next prime is 18237692227. The reversal of 18237692209 is 90229673281.

The square root of 18237692209 is 135047.

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., 1537816225 + 16699875984 = 39215^2 + 129228^2 .

It is not a de Polignac number, because 18237692209 - 2²⁹ = 17700821297 is a prime.

It is a super-2 number, since 2×18237692209² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18237692909) 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, 1479379 + ... + 1491655.

Almost surely, 2^18237692209 is an apocalyptic number.

18237692209 is the 135047-th square number.

18237692209 is the 67524-th centered octagonal number.

It is an amenable number.

18237692209 is a deficient number, since it is larger than the sum of its proper divisors (1810329722).

18237692209 is an frugal number, since it uses more digits than its factorization.

18237692209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24576 (or 12288 counting only the distinct ones).

The product of its (nonzero) digits is 653184, while the sum is 49.

Multiplying 18237692209 by its sum of digits (49), we get a square (893646918241 = 945329²).

The spelling of 18237692209 in words is "eighteen billion, two hundred thirty-seven million, six hundred ninety-two thousand, two hundred nine".