18240220387 has 4 divisors (see below), whose sum is σ = 18247788216. Its totient is φ = 18232652560.

The previous prime is 18240220337. The next prime is 18240220469. The reversal of 18240220387 is 78302204281.

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-18240220387 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18240220337) 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, 3780298 + ... + 3785119.

It is an arithmetic number, because the mean of its divisors is an integer number (4561947054).

Almost surely, 2^18240220387 is an apocalyptic number.

18240220387 is a deficient number, since it is larger than the sum of its proper divisors (7567829).

18240220387 is an equidigital number, since it uses as much as digits as its factorization.

18240220387 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7567828.

The product of its (nonzero) digits is 43008, while the sum is 37.

The spelling of 18240220387 in words is "eighteen billion, two hundred forty million, two hundred twenty thousand, three hundred eighty-seven".