216190978 has 16 divisors (see below), whose sum is σ = 326900376. Its totient is φ = 107228160.

The previous prime is 216190973. The next prime is 216190999. The reversal of 216190978 is 879091612.

216190978 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 178035649 + 38155329 = 13343^2 + 6177^2 .

It is not an unprimeable number, because it can be changed into a prime (216190973) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 150150 + ... + 151582.

Almost surely, 2^216190978 is an apocalyptic number.

216190978 is a deficient number, since it is larger than the sum of its proper divisors (110709398).

216190978 is a wasteful number, since it uses less digits than its factorization.

216190978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1989.

The product of its (nonzero) digits is 54432, while the sum is 43.

The square root of 216190978 is about 14703.4342246973. The cubic root of 216190978 is about 600.1767793914.

It can be divided in two parts, 2161 and 90978, that added together give a palindrome (93139).

The spelling of 216190978 in words is "two hundred sixteen million, one hundred ninety thousand, nine hundred seventy-eight".