18121000 has 32 divisors (see below), whose sum is σ = 42405480. Its totient is φ = 7248000.

The previous prime is 18120989. The next prime is 18121039. The reversal of 18121000 is 12181.

It can be written as a sum of positive squares in 4 ways, for example, as 4088484 + 14032516 = 2022^2 + 3746^2 .

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 8061 + ... + 10060.

Almost surely, 2^18121000 is an apocalyptic number.

18121000 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18121000 is an abundant number, since it is smaller than the sum of its proper divisors (24284480).

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

18121000 is a wasteful number, since it uses less digits than its factorization.

18121000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18142 (or 18128 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 13.

The square root of 18121000 is about 4256.8767893844. The cubic root of 18121000 is about 262.6600686614.

Adding to 18121000 its reverse (12181), we get a palindrome (18133181).

The spelling of 18121000 in words is "eighteen million, one hundred twenty-one thousand".