18421195021 has 4 divisors (see below), whose sum is σ = 18680648544. Its totient is φ = 18161741500.

The previous prime is 18421194997. The next prime is 18421195031. The reversal of 18421195021 is 12059112481.

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: 12059112481 = 13 ⋅927624037.

It is a cyclic number.

It is not a de Polignac number, because 18421195021 - 2¹¹ = 18421192973 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 (18421195031) 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, 129726655 + ... + 129726796.

It is an arithmetic number, because the mean of its divisors is an integer number (4670162136).

Almost surely, 2^18421195021 is an apocalyptic number.

It is an amenable number.

18421195021 is a deficient number, since it is larger than the sum of its proper divisors (259453523).

18421195021 is an equidigital number, since it uses as much as digits as its factorization.

18421195021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 259453522.

The product of its (nonzero) digits is 5760, while the sum is 34.

The spelling of 18421195021 in words is "eighteen billion, four hundred twenty-one million, one hundred ninety-five thousand, twenty-one".