216838978 has 8 divisors (see below), whose sum is σ = 344391372. Its totient is φ = 102041856.

The previous prime is 216838967. The next prime is 216838991. The reversal of 216838978 is 879838612.

216838978 is digitally balanced in base 2, 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 2 ways, for example, as 201838849 + 15000129 = 14207^2 + 3873^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3188775 + ... + 3188842.

Almost surely, 2^216838978 is an apocalyptic number.

216838978 is a deficient number, since it is larger than the sum of its proper divisors (127552394).

216838978 is a wasteful number, since it uses less digits than its factorization.

216838978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6377636.

The product of its digits is 1161216, while the sum is 52.

The square root of 216838978 is about 14725.4534055831. The cubic root of 216838978 is about 600.7758278676.

The spelling of 216838978 in words is "two hundred sixteen million, eight hundred thirty-eight thousand, nine hundred seventy-eight".