18781943 has 4 divisors (see below), whose sum is σ = 18790848. Its totient is φ = 18773040.

The previous prime is 18781921. The next prime is 18781967. The reversal of 18781943 is 34918781.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 18781943 - 2¹⁶ = 18716407 is a prime.

It is a super-2 number, since 2×18781943² = 705522765710498, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18781943.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18781913) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 698 + ... + 6168.

It is an arithmetic number, because the mean of its divisors is an integer number (4697712).

Almost surely, 2^18781943 is an apocalyptic number.

18781943 is a deficient number, since it is larger than the sum of its proper divisors (8905).

18781943 is an equidigital number, since it uses as much as digits as its factorization.

18781943 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8904.

The product of its digits is 48384, while the sum is 41.

The square root of 18781943 is about 4333.8139092490. The cubic root of 18781943 is about 265.8154211607.

The spelling of 18781943 in words is "eighteen million, seven hundred eighty-one thousand, nine hundred forty-three".