18786989 has 8 divisors (see below), whose sum is σ = 21422520. Its totient is φ = 16321536.

The previous prime is 18786973. The next prime is 18786997. The reversal of 18786989 is 98968781.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 2449225 + 16337764 = 1565^2 + 4042^2 .

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 18786989 - 2⁴ = 18786973 is a prime.

It is a super-2 number, since 2×18786989² = 705901911372242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18786919) 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, 42284 + ... + 42725.

It is an arithmetic number, because the mean of its divisors is an integer number (2677815).

Almost surely, 2^18786989 is an apocalyptic number.

It is an amenable number.

18786989 is a deficient number, since it is larger than the sum of its proper divisors (2635531).

18786989 is a wasteful number, since it uses less digits than its factorization.

18786989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85039.

The product of its digits is 1741824, while the sum is 56.

The square root of 18786989 is about 4334.3960363585. The cubic root of 18786989 is about 265.8392238900.

The spelling of 18786989 in words is "eighteen million, seven hundred eighty-six thousand, nine hundred eighty-nine".