216795821 has 6 divisors (see below), whose sum is σ = 238296366. Its totient is φ = 197087000.

The previous prime is 216795797. The next prime is 216795841. The reversal of 216795821 is 128597612.

216795821 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 only one way, i.e., 214036900 + 2758921 = 14630^2 + 1661^2 .

It is not a de Polignac number, because 216795821 - 2²² = 212601517 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216795841) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 895730 + ... + 895971.

It is an arithmetic number, because the mean of its divisors is an integer number (39716061).

Almost surely, 2^216795821 is an apocalyptic number.

It is an amenable number.

216795821 is a deficient number, since it is larger than the sum of its proper divisors (21500545).

216795821 is a wasteful number, since it uses less digits than its factorization.

216795821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1791723 (or 1791712 counting only the distinct ones).

The product of its digits is 60480, while the sum is 41.

The square root of 216795821 is about 14723.9879448470. The cubic root of 216795821 is about 600.7359681786.

The spelling of 216795821 in words is "two hundred sixteen million, seven hundred ninety-five thousand, eight hundred twenty-one".