18745281 has 12 divisors (see below), whose sum is σ = 28010580. Its totient is φ = 12065760.

The previous prime is 18745277. The next prime is 18745283. The reversal of 18745281 is 18254781.

It can be written as a sum of positive squares in 2 ways, for example, as 2944656 + 15800625 = 1716^2 + 3975^2 .

It is not a de Polignac number, because 18745281 - 2² = 18745277 is a prime.

It is a super-2 number, since 2×18745281² = 702771119537922, which contains 22 as substring.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (18745283) 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 11 ways as a sum of consecutive naturals, for example, 35650 + ... + 36171.

It is an arithmetic number, because the mean of its divisors is an integer number (2334215).

Almost surely, 2^18745281 is an apocalyptic number.

It is an amenable number.

18745281 is a deficient number, since it is larger than the sum of its proper divisors (9265299).

18745281 is a wasteful number, since it uses less digits than its factorization.

18745281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71856 (or 71853 counting only the distinct ones).

The product of its digits is 17920, while the sum is 36.

The square root of 18745281 is about 4329.5820814485. The cubic root of 18745281 is about 265.6423529332.

The spelling of 18745281 in words is "eighteen million, seven hundred forty-five thousand, two hundred eighty-one".