216890212978 has 4 divisors (see below), whose sum is σ = 325335319470. Its totient is φ = 108445106488.

The previous prime is 216890212961. The next prime is 216890212993. The reversal of 216890212978 is 879212098612.

216890212978 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 201181852089 + 15708360889 = 448533^2 + 125333^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 54222553243 + ... + 54222553246.

Almost surely, 2^216890212978 is an apocalyptic number.

216890212978 is a deficient number, since it is larger than the sum of its proper divisors (108445106492).

216890212978 is a wasteful number, since it uses less digits than its factorization.

216890212978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 108445106491.

The product of its (nonzero) digits is 1741824, while the sum is 55.

The spelling of 216890212978 in words is "two hundred sixteen billion, eight hundred ninety million, two hundred twelve thousand, nine hundred seventy-eight".