18218365640407 has 4 divisors (see below), whose sum is σ = 18218376165240. Its totient is φ = 18218355115576.

The previous prime is 18218365640399. The next prime is 18218365640429. The reversal of 18218365640407 is 70404656381281.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 18218365640407 - 2³ = 18218365640399 is a prime.

It is a super-2 number, since 2×18218365640407² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18218365640507) 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, 1985932 + ... + 6354577.

It is an arithmetic number, because the mean of its divisors is an integer number (4554594041310).

Almost surely, 2^{18218365640407} is an apocalyptic number.

18218365640407 is a deficient number, since it is larger than the sum of its proper divisors (10524833).

18218365640407 is an equidigital number, since it uses as much as digits as its factorization.

18218365640407 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10524832.

The product of its (nonzero) digits is 7741440, while the sum is 55.

The spelling of 18218365640407 in words is "eighteen trillion, two hundred eighteen billion, three hundred sixty-five million, six hundred forty thousand, four hundred seven".