216778386 has 16 divisors (see below), whose sum is σ = 472971168. Its totient is φ = 65690400.

The previous prime is 216778379. The next prime is 216778411. The reversal of 216778386 is 683877612.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1642195 + ... + 1642326.

It is an arithmetic number, because the mean of its divisors is an integer number (29560698).

Almost surely, 2^216778386 is an apocalyptic number.

216778386 is an abundant number, since it is smaller than the sum of its proper divisors (256192782).

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

216778386 is a wasteful number, since it uses less digits than its factorization.

216778386 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3284537.

The product of its digits is 677376, while the sum is 48.

The square root of 216778386 is about 14723.3958718768. The cubic root of 216778386 is about 600.7198637593.

The spelling of 216778386 in words is "two hundred sixteen million, seven hundred seventy-eight thousand, three hundred eighty-six".