18943894 has 4 divisors (see below), whose sum is σ = 28415844. Its totient is φ = 9471946.

The previous prime is 18943879. The next prime is 18943901. The reversal of 18943894 is 49834981.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 49834981 = 7 ⋅7119283.

It is a super-2 number, since 2×18943894² = 717742239766472, which contains 22 as substring.

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

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 4735972 + ... + 4735975.

It is an arithmetic number, because the mean of its divisors is an integer number (7103961).

Almost surely, 2^18943894 is an apocalyptic number.

18943894 is a deficient number, since it is larger than the sum of its proper divisors (9471950).

18943894 is an equidigital number, since it uses as much as digits as its factorization.

18943894 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9471949.

The product of its digits is 248832, while the sum is 46.

The square root of 18943894 is about 4352.4583857861. The cubic root of 18943894 is about 266.5772509242.

The spelling of 18943894 in words is "eighteen million, nine hundred forty-three thousand, eight hundred ninety-four".