18121887 has 40 divisors (see below), whose sum is σ = 31967232. Its totient is φ = 10011600.

The previous prime is 18121867. The next prime is 18121891. The reversal of 18121887 is 78812181.

It is not a de Polignac number, because 18121887 - 2⁷ = 18121759 is a prime.

It is a super-3 number, since 3×18121887³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18121867) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 17062 + ... + 18092.

Almost surely, 2^18121887 is an apocalyptic number.

18121887 is a deficient number, since it is larger than the sum of its proper divisors (13845345).

18121887 is a wasteful number, since it uses less digits than its factorization.

18121887 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1081 (or 1072 counting only the distinct ones).

The product of its digits is 7168, while the sum is 36.

The square root of 18121887 is about 4256.9809724733. The cubic root of 18121887 is about 262.6643542173.

The spelling of 18121887 in words is "eighteen million, one hundred twenty-one thousand, eight hundred eighty-seven".