18978847 has 6 divisors (see below), whose sum is σ = 19656728. Its totient is φ = 18323592.

The previous prime is 18978811. The next prime is 18978857. The reversal of 18978847 is 74887981.

It is not a de Polignac number, because 18978847 - 2⁷ = 18978719 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18978794 and 18978803.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18978857) 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 5 ways as a sum of consecutive naturals, for example, 10443 + ... + 12124.

Almost surely, 2^18978847 is an apocalyptic number.

18978847 is a deficient number, since it is larger than the sum of its proper divisors (677881).

18978847 is an equidigital number, since it uses as much as digits as its factorization.

18978847 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22625 (or 22596 counting only the distinct ones).

The product of its digits is 903168, while the sum is 52.

The square root of 18978847 is about 4356.4718523135. The cubic root of 18978847 is about 266.7411023109.

The spelling of 18978847 in words is "eighteen million, nine hundred seventy-eight thousand, eight hundred forty-seven".