18427012221 has 4 divisors (see below), whose sum is σ = 24569349632. Its totient is φ = 12284674812.

The previous prime is 18427012217. The next prime is 18427012271. The reversal of 18427012221 is 12221072481.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12221072481 = 3 ⋅4073690827.

It is not a de Polignac number, because 18427012221 - 2² = 18427012217 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 (18427012271) 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, 3071168701 + ... + 3071168706.

It is an arithmetic number, because the mean of its divisors is an integer number (6142337408).

Almost surely, 2^18427012221 is an apocalyptic number.

It is an amenable number.

18427012221 is a deficient number, since it is larger than the sum of its proper divisors (6142337411).

18427012221 is an equidigital number, since it uses as much as digits as its factorization.

18427012221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6142337410.

The product of its (nonzero) digits is 3584, while the sum is 30.

The spelling of 18427012221 in words is "eighteen billion, four hundred twenty-seven million, twelve thousand, two hundred twenty-one".