18240123137 has 4 divisors (see below), whose sum is σ = 18733099476. Its totient is φ = 17747146800.

The previous prime is 18240123133. The next prime is 18240123149. The reversal of 18240123137 is 73132104281.

It is a Cunningham number, because it is equal to 135056²+1.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 73132104281 = 79 ⋅925722839.

It can be written as a sum of positive squares in 2 ways, for example, as 16321595536 + 1918527601 = 127756^2 + 43801^2 .

It is a cyclic number.

It is not a de Polignac number, because 18240123137 - 2² = 18240123133 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18240123133) 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, 246488114 + ... + 246488187.

It is an arithmetic number, because the mean of its divisors is an integer number (4683274869).

Almost surely, 2^18240123137 is an apocalyptic number.

It is an amenable number.

18240123137 is a deficient number, since it is larger than the sum of its proper divisors (492976339).

18240123137 is an equidigital number, since it uses as much as digits as its factorization.

18240123137 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 492976338.

The product of its (nonzero) digits is 8064, while the sum is 32.

The spelling of 18240123137 in words is "eighteen billion, two hundred forty million, one hundred twenty-three thousand, one hundred thirty-seven".