18398778 has 16 divisors (see below), whose sum is σ = 36974496. Its totient is φ = 6103440.

The previous prime is 18398767. The next prime is 18398813. The reversal of 18398778 is 87789381.

It is a self number, because there is not a number n which added to its sum of digits gives 18398778.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 6001 + ... + 8532.

It is an arithmetic number, because the mean of its divisors is an integer number (2310906).

Almost surely, 2^18398778 is an apocalyptic number.

18398778 is an abundant number, since it is smaller than the sum of its proper divisors (18575718).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18398778 is a wasteful number, since it uses less digits than its factorization.

18398778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14749.

The product of its digits is 677376, while the sum is 51.

The square root of 18398778 is about 4289.3796754309. The cubic root of 18398778 is about 263.9953798549.

The spelling of 18398778 in words is "eighteen million, three hundred ninety-eight thousand, seven hundred seventy-eight".