216735978 has 32 divisors (see below), whose sum is σ = 440796096. Its totient is φ = 71031168.

The previous prime is 216735977. The next prime is 216735997. The reversal of 216735978 is 879537612.

216735978 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (216735977) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 193476 + ... + 194592.

It is an arithmetic number, because the mean of its divisors is an integer number (13774878).

Almost surely, 2^216735978 is an apocalyptic number.

216735978 is an abundant number, since it is smaller than the sum of its proper divisors (224060118).

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

216735978 is a wasteful number, since it uses less digits than its factorization.

216735978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1638.

The product of its digits is 635040, while the sum is 48.

The square root of 216735978 is about 14721.9556445467. The cubic root of 216735978 is about 600.6806885908.

The spelling of 216735978 in words is "two hundred sixteen million, seven hundred thirty-five thousand, nine hundred seventy-eight".