18781434 has 24 divisors (see below), whose sum is σ = 46506720. Its totient is φ = 5366088.

The previous prime is 18781429. The next prime is 18781457. The reversal of 18781434 is 43418781.

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

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 74404 + ... + 74655.

It is an arithmetic number, because the mean of its divisors is an integer number (1937780).

Almost surely, 2^18781434 is an apocalyptic number.

18781434 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

18781434 is an abundant number, since it is smaller than the sum of its proper divisors (27725286).

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

18781434 is a wasteful number, since it uses less digits than its factorization.

18781434 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149074 (or 149071 counting only the distinct ones).

The product of its digits is 21504, while the sum is 36.

The square root of 18781434 is about 4333.7551845945. The cubic root of 18781434 is about 265.8130198957.

The spelling of 18781434 in words is "eighteen million, seven hundred eighty-one thousand, four hundred thirty-four".