18443813 has 8 divisors (see below), whose sum is σ = 19744800. Its totient is φ = 17175888.

The previous prime is 18443801. The next prime is 18443819. The reversal of 18443813 is 31834481.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18443813 - 2⁶ = 18443749 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18443813.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18443819) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7106 + ... + 9347.

It is an arithmetic number, because the mean of its divisors is an integer number (2468100).

Almost surely, 2^18443813 is an apocalyptic number.

It is an amenable number.

18443813 is a deficient number, since it is larger than the sum of its proper divisors (1300987).

18443813 is a wasteful number, since it uses less digits than its factorization.

18443813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16531.

The product of its digits is 9216, while the sum is 32.

The square root of 18443813 is about 4294.6260605552. The cubic root of 18443813 is about 264.2105996695.

The spelling of 18443813 in words is "eighteen million, four hundred forty-three thousand, eight hundred thirteen".