18540778 has 16 divisors (see below), whose sum is σ = 30005640. Its totient is φ = 8559616.

The previous prime is 18540757. The next prime is 18540779. The reversal of 18540778 is 87704581.

It can be written as a sum of positive squares in 4 ways, for example, as 18378369 + 162409 = 4287^2 + 403^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 18540778.

It is not an unprimeable number, because it can be changed into a prime (18540779) 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 7 ways as a sum of consecutive naturals, for example, 3343 + ... + 6946.

Almost surely, 2^18540778 is an apocalyptic number.

18540778 is a deficient number, since it is larger than the sum of its proper divisors (11464862).

18540778 is a wasteful number, since it uses less digits than its factorization.

18540778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10361.

The product of its (nonzero) digits is 62720, while the sum is 40.

The square root of 18540778 is about 4305.9003704220. The cubic root of 18540778 is about 264.6728037232.

The spelling of 18540778 in words is "eighteen million, five hundred forty thousand, seven hundred seventy-eight".