18341287821 has 6 divisors (see below), whose sum is σ = 26492971310. Its totient is φ = 12227525208.

The previous prime is 18341287819. The next prime is 18341287823. The reversal of 18341287821 is 12878214381.

18341287821 is a `hidden beast` number, since 1 + 8 + 341 + 287 + 8 + 21 = 666.

It is an interprime number because it is at equal distance from previous prime (18341287819) and next prime (18341287823).

It can be written as a sum of positive squares in only one way, i.e., 15147455625 + 3193832196 = 123075^2 + 56514^2 .

It is not a de Polignac number, because 18341287821 - 2¹ = 18341287819 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 (18341287823) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1018960426 + ... + 1018960443.

Almost surely, 2^18341287821 is an apocalyptic number.

It is an amenable number.

18341287821 is a deficient number, since it is larger than the sum of its proper divisors (8151683489).

18341287821 is a wasteful number, since it uses less digits than its factorization.

18341287821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2037920875 (or 2037920872 counting only the distinct ones).

The product of its digits is 172032, while the sum is 45.

The spelling of 18341287821 in words is "eighteen billion, three hundred forty-one million, two hundred eighty-seven thousand, eight hundred twenty-one".