18986657 has 4 divisors (see below), whose sum is σ = 18999060. Its totient is φ = 18974256.

The previous prime is 18986651. The next prime is 18986689. The reversal of 18986657 is 75668981.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 75668981 = 113 ⋅669637.

It can be written as a sum of positive squares in 2 ways, for example, as 18627856 + 358801 = 4316^2 + 599^2 .

It is a cyclic number.

It is not a de Polignac number, because 18986657 - 2⁴ = 18986641 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18986651) by changing a digit.

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 in 3 ways as a sum of consecutive naturals, for example, 3518 + ... + 7095.

It is an arithmetic number, because the mean of its divisors is an integer number (4749765).

Almost surely, 2^18986657 is an apocalyptic number.

It is an amenable number.

18986657 is a deficient number, since it is larger than the sum of its proper divisors (12403).

18986657 is a wasteful number, since it uses less digits than its factorization.

18986657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12402.

The product of its digits is 725760, while the sum is 50.

The square root of 18986657 is about 4357.3681276661. The cubic root of 18986657 is about 266.7776862388. Note that the first 3 decimals are identical.

The spelling of 18986657 in words is "eighteen million, nine hundred eighty-six thousand, six hundred fifty-seven".