18977689 has 4 divisors (see below), whose sum is σ = 19098724. Its totient is φ = 18856656.

The previous prime is 18977639. The next prime is 18977723. The reversal of 18977689 is 98677981.

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 5139289 + 13838400 = 2267^2 + 3720^2 .

It is a cyclic number.

It is not a de Polignac number, because 18977689 - 2¹¹ = 18975641 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18977639) 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, 60282 + ... + 60595.

It is an arithmetic number, because the mean of its divisors is an integer number (4774681).

Almost surely, 2^18977689 is an apocalyptic number.

It is an amenable number.

18977689 is a deficient number, since it is larger than the sum of its proper divisors (121035).

18977689 is a wasteful number, since it uses less digits than its factorization.

18977689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121034.

The product of its digits is 1524096, while the sum is 55.

The square root of 18977689 is about 4356.3389445726. The cubic root of 18977689 is about 266.7356771046.

The spelling of 18977689 in words is "eighteen million, nine hundred seventy-seven thousand, six hundred eighty-nine".