18121550 has 12 divisors (see below), whose sum is σ = 33706176. Its totient is φ = 7248600.

The previous prime is 18121531. The next prime is 18121559. The reversal of 18121550 is 5512181.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18121559) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 181166 + ... + 181265.

It is an arithmetic number, because the mean of its divisors is an integer number (2808848).

Almost surely, 2^18121550 is an apocalyptic number.

18121550 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18121550 is a deficient number, since it is larger than the sum of its proper divisors (15584626).

18121550 is a wasteful number, since it uses less digits than its factorization.

18121550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 362443 (or 362438 counting only the distinct ones).

The product of its (nonzero) digits is 400, while the sum is 23.

The square root of 18121550 is about 4256.9413902472. The cubic root of 18121550 is about 262.6627260124.

The spelling of 18121550 in words is "eighteen million, one hundred twenty-one thousand, five hundred fifty".