18364747421 has 4 divisors (see below), whose sum is σ = 18554074812. Its totient is φ = 18175420032.

The previous prime is 18364747391. The next prime is 18364747439. The reversal of 18364747421 is 12474746381.

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

It can be written as a sum of positive squares in 2 ways, for example, as 5656694521 + 12708052900 = 75211^2 + 112730^2 .

It is a cyclic number.

It is not a de Polignac number, because 18364747421 - 2³⁴ = 1184878237 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18364747441) 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, 94663550 + ... + 94663743.

It is an arithmetic number, because the mean of its divisors is an integer number (4638518703).

Almost surely, 2^18364747421 is an apocalyptic number.

It is an amenable number.

18364747421 is a deficient number, since it is larger than the sum of its proper divisors (189327391).

18364747421 is an equidigital number, since it uses as much as digits as its factorization.

18364747421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 189327390.

The product of its digits is 903168, while the sum is 47.

The spelling of 18364747421 in words is "eighteen billion, three hundred sixty-four million, seven hundred forty-seven thousand, four hundred twenty-one".