18321858 has 12 divisors (see below), whose sum is σ = 39697398. Its totient is φ = 6107280.

The previous prime is 18321857. The next prime is 18321883. The reversal of 18321858 is 85812381.

It can be written as a sum of positive squares in only one way, i.e., 18122049 + 199809 = 4257^2 + 447^2 .

It is an alternating number because its digits alternate between odd and even.

It is not an unprimeable number, because it can be changed into a prime (18321857) 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 5 ways as a sum of consecutive naturals, for example, 508923 + ... + 508958.

Almost surely, 2^18321858 is an apocalyptic number.

18321858 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

18321858 is an abundant number, since it is smaller than the sum of its proper divisors (21375540).

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

18321858 is a wasteful number, since it uses less digits than its factorization.

18321858 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1017889 (or 1017886 counting only the distinct ones).

The product of its digits is 15360, while the sum is 36.

The square root of 18321858 is about 4280.4039528998. The cubic root of 18321858 is about 263.6269697154.

The spelling of 18321858 in words is "eighteen million, three hundred twenty-one thousand, eight hundred fifty-eight".