18420155 has 12 divisors (see below), whose sum is σ = 23936400. Its totient is φ = 13601952.

The previous prime is 18420151. The next prime is 18420161. The reversal of 18420155 is 55102481.

18420155 is an esthetic number in base 4, because in such base its adjacent digits differ by 1.

It is not a de Polignac number, because 18420155 - 2² = 18420151 is a prime.

It is a super-2 number, since 2×18420155² = 678604220448050, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (18420151) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10055 + ... + 11744.

It is an arithmetic number, because the mean of its divisors is an integer number (1994700).

Almost surely, 2^18420155 is an apocalyptic number.

18420155 is a deficient number, since it is larger than the sum of its proper divisors (5516245).

18420155 is a wasteful number, since it uses less digits than its factorization.

18420155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21830 (or 21817 counting only the distinct ones).

The product of its (nonzero) digits is 1600, while the sum is 26.

The square root of 18420155 is about 4291.8708042065. The cubic root of 18420155 is about 264.0975831099.

The spelling of 18420155 in words is "eighteen million, four hundred twenty thousand, one hundred fifty-five".