18216878 has 4 divisors (see below), whose sum is σ = 27325320. Its totient is φ = 9108438.

The previous prime is 18216859. The next prime is 18216881. The reversal of 18216878 is 87861281.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 87861281 = 2381 ⋅36901.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4554218 + ... + 4554221.

It is an arithmetic number, because the mean of its divisors is an integer number (6831330).

Almost surely, 2^18216878 is an apocalyptic number.

18216878 is a deficient number, since it is larger than the sum of its proper divisors (9108442).

18216878 is an equidigital number, since it uses as much as digits as its factorization.

18216878 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9108441.

The product of its digits is 43008, while the sum is 41.

The square root of 18216878 is about 4268.1234752523. The cubic root of 18216878 is about 263.1224978369.

The spelling of 18216878 in words is "eighteen million, two hundred sixteen thousand, eight hundred seventy-eight".