216798121 has 4 divisors (see below), whose sum is σ = 216831492. Its totient is φ = 216764752.

The previous prime is 216798107. The next prime is 216798139. The reversal of 216798121 is 121897612.

216798121 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 2 ways, for example, as 120758121 + 96040000 = 10989^2 + 9800^2 .

It is a cyclic number.

It is not a de Polignac number, because 216798121 - 2⁵ = 216798089 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216798521) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3430 + ... + 21103.

It is an arithmetic number, because the mean of its divisors is an integer number (54207873).

Almost surely, 2^216798121 is an apocalyptic number.

It is an amenable number.

216798121 is a deficient number, since it is larger than the sum of its proper divisors (33371).

216798121 is an equidigital number, since it uses as much as digits as its factorization.

216798121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33370.

The product of its digits is 12096, while the sum is 37.

The square root of 216798121 is about 14724.0660484800. The cubic root of 216798121 is about 600.7380925858.

The spelling of 216798121 in words is "two hundred sixteen million, seven hundred ninety-eight thousand, one hundred twenty-one".