18818977 has 4 divisors (see below), whose sum is σ = 19327636. Its totient is φ = 18310320.

The previous prime is 18818939. The next prime is 18819007. The reversal of 18818977 is 77981881.

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 15374241 + 3444736 = 3921^2 + 1856^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18818977 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18818977.

It is not an unprimeable number, because it can be changed into a prime (18810977) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 254274 + ... + 254347.

It is an arithmetic number, because the mean of its divisors is an integer number (4831909).

Almost surely, 2^18818977 is an apocalyptic number.

It is an amenable number.

18818977 is a deficient number, since it is larger than the sum of its proper divisors (508659).

18818977 is an equidigital number, since it uses as much as digits as its factorization.

18818977 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 508658.

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

The square root of 18818977 is about 4338.0844851155. The cubic root of 18818977 is about 265.9900169619.

The spelling of 18818977 in words is "eighteen million, eight hundred eighteen thousand, nine hundred seventy-seven".