18938461 has 4 divisors (see below), whose sum is σ = 19106172. Its totient is φ = 18770752.

The previous prime is 18938443. The next prime is 18938471. The reversal of 18938461 is 16483981.

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

It can be written as a sum of positive squares in 2 ways, for example, as 1674436 + 17264025 = 1294^2 + 4155^2 .

It is a cyclic number.

It is not a de Polignac number, because 18938461 - 2⁵ = 18938429 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18938431) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 83686 + ... + 83911.

It is an arithmetic number, because the mean of its divisors is an integer number (4776543).

Almost surely, 2^18938461 is an apocalyptic number.

It is an amenable number.

18938461 is a deficient number, since it is larger than the sum of its proper divisors (167711).

18938461 is a wasteful number, since it uses less digits than its factorization.

18938461 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 167710.

The product of its digits is 41472, while the sum is 40.

The square root of 18938461 is about 4351.8342109966. The cubic root of 18938461 is about 266.5517642127.

The spelling of 18938461 in words is "eighteen million, nine hundred thirty-eight thousand, four hundred sixty-one".