18121992 has 64 divisors (see below), whose sum is σ = 52099200. Its totient is φ = 5145600.

The previous prime is 18121979. The next prime is 18121993. The reversal of 18121992 is 29912181.

It is not an unprimeable number, because it can be changed into a prime (18121993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 44992 + ... + 45392.

It is an arithmetic number, because the mean of its divisors is an integer number (814050).

Almost surely, 2^18121992 is an apocalyptic number.

18121992 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18121992, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26049600).

18121992 is an abundant number, since it is smaller than the sum of its proper divisors (33977208).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18121992 is a wasteful number, since it uses less digits than its factorization.

18121992 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 686 (or 682 counting only the distinct ones).

The product of its digits is 2592, while the sum is 33.

The square root of 18121992 is about 4256.9933051392. The cubic root of 18121992 is about 262.6648615174.

The spelling of 18121992 in words is "eighteen million, one hundred twenty-one thousand, nine hundred ninety-two".