18105112021 has 4 divisors (see below), whose sum is σ = 18108114112. Its totient is φ = 18102109932.

The previous prime is 18105111961. The next prime is 18105112049. The reversal of 18105112021 is 12021150181.

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.

It is a cyclic number.

It is not a de Polignac number, because 18105112021 - 2⁹ = 18105111509 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18105111983 and 18105112001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18105112121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1491981 + ... + 1504066.

It is an arithmetic number, because the mean of its divisors is an integer number (4527028528).

Almost surely, 2^18105112021 is an apocalyptic number.

It is an amenable number.

18105112021 is a deficient number, since it is larger than the sum of its proper divisors (3002091).

18105112021 is an equidigital number, since it uses as much as digits as its factorization.

18105112021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3002090.

The product of its (nonzero) digits is 160, while the sum is 22.

The spelling of 18105112021 in words is "eighteen billion, one hundred five million, one hundred twelve thousand, twenty-one".