18718789 has 4 divisors (see below), whose sum is σ = 18884556. Its totient is φ = 18553024.

The previous prime is 18718787. The next prime is 18718793. The reversal of 18718789 is 98781781.

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 10510564 + 8208225 = 3242^2 + 2865^2 .

It is a cyclic number.

It is not a de Polignac number, because 18718789 - 2¹ = 18718787 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18718787) 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, 82714 + ... + 82939.

It is an arithmetic number, because the mean of its divisors is an integer number (4721139).

Almost surely, 2^18718789 is an apocalyptic number.

It is an amenable number.

18718789 is a deficient number, since it is larger than the sum of its proper divisors (165767).

18718789 is a wasteful number, since it uses less digits than its factorization.

18718789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165766.

The product of its digits is 225792, while the sum is 49.

The square root of 18718789 is about 4326.5215820564. The cubic root of 18718789 is about 265.5171531554.

The spelling of 18718789 in words is "eighteen million, seven hundred eighteen thousand, seven hundred eighty-nine".