18115729 has 4 divisors (see below), whose sum is σ = 18191140. Its totient is φ = 18040320.

The previous prime is 18115723. The next prime is 18115733. The reversal of 18115729 is 92751181.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 92751181 = 2221 ⋅41761.

It can be written as a sum of positive squares in 2 ways, for example, as 12616704 + 5499025 = 3552^2 + 2345^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18115729 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18115694 and 18115703.

It is not an unprimeable number, because it can be changed into a prime (18115723) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 37344 + ... + 37825.

It is an arithmetic number, because the mean of its divisors is an integer number (4547785).

Almost surely, 2^18115729 is an apocalyptic number.

It is an amenable number.

18115729 is a deficient number, since it is larger than the sum of its proper divisors (75411).

18115729 is an equidigital number, since it uses as much as digits as its factorization.

18115729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75410.

The product of its digits is 5040, while the sum is 34.

The square root of 18115729 is about 4256.2576284807. The cubic root of 18115729 is about 262.6345988477.

The spelling of 18115729 in words is "eighteen million, one hundred fifteen thousand, seven hundred twenty-nine".