18581842 has 4 divisors (see below), whose sum is σ = 27872766. Its totient is φ = 9290920.

The previous prime is 18581821. The next prime is 18581851. The reversal of 18581842 is 24818581.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 16394401 + 2187441 = 4049^2 + 1479^2 .

It is a super-2 number, since 2×18581842² = 690569704225928, which contains 22 as substring.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 4645459 + ... + 4645462.

Almost surely, 2^18581842 is an apocalyptic number.

18581842 is a deficient number, since it is larger than the sum of its proper divisors (9290924).

18581842 is an equidigital number, since it uses as much as digits as its factorization.

18581842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9290923.

The product of its digits is 20480, while the sum is 37.

The square root of 18581842 is about 4310.6660738220. Note that the first 3 decimals coincide. The cubic root of 18581842 is about 264.8680582054.

The spelling of 18581842 in words is "eighteen million, five hundred eighty-one thousand, eight hundred forty-two".