18721234 has 12 divisors (see below), whose sum is σ = 32666814. Its totient is φ = 8023344.

The previous prime is 18721229. The next prime is 18721249. The reversal of 18721234 is 43212781.

It can be written as a sum of positive squares in only one way, i.e., 9703225 + 9018009 = 3115^2 + 3003^2 .

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 95419 + ... + 95614.

Almost surely, 2^18721234 is an apocalyptic number.

18721234 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

18721234 is a deficient number, since it is larger than the sum of its proper divisors (13945580).

18721234 is a wasteful number, since it uses less digits than its factorization.

18721234 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 191049 (or 191042 counting only the distinct ones).

The product of its digits is 2688, while the sum is 28.

The square root of 18721234 is about 4326.8041323822. The cubic root of 18721234 is about 265.5287130410.

The spelling of 18721234 in words is "eighteen million, seven hundred twenty-one thousand, two hundred thirty-four".