18156242399 has 4 divisors (see below), whose sum is σ = 18248406264. Its totient is φ = 18064078536.

The previous prime is 18156242381. The next prime is 18156242407. The reversal of 18156242399 is 99324265181.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18156242399 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18156242359) 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, 46081637 + ... + 46082030.

It is an arithmetic number, because the mean of its divisors is an integer number (4562101566).

Almost surely, 2^18156242399 is an apocalyptic number.

18156242399 is a deficient number, since it is larger than the sum of its proper divisors (92163865).

18156242399 is an equidigital number, since it uses as much as digits as its factorization.

18156242399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92163864.

The product of its digits is 933120, while the sum is 50.

The spelling of 18156242399 in words is "eighteen billion, one hundred fifty-six million, two hundred forty-two thousand, three hundred ninety-nine".