216821289 has 8 divisors (see below), whose sum is σ = 289516192. Its totient is φ = 144336960.

The previous prime is 216821273. The next prime is 216821303. The reversal of 216821289 is 982128612.

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

It is not a de Polignac number, because 216821289 - 2⁴ = 216821273 is a prime.

It is a super-2 number, since 2×216821289² = 94022942727243042, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216821249) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 50224 + ... + 54369.

It is an arithmetic number, because the mean of its divisors is an integer number (36189524).

Almost surely, 2^216821289 is an apocalyptic number.

It is an amenable number.

216821289 is a deficient number, since it is larger than the sum of its proper divisors (72694903).

216821289 is a wasteful number, since it uses less digits than its factorization.

216821289 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 105287.

The product of its digits is 27648, while the sum is 39.

The square root of 216821289 is about 14724.8527666663. The cubic root of 216821289 is about 600.7594909945.

The spelling of 216821289 in words is "two hundred sixteen million, eight hundred twenty-one thousand, two hundred eighty-nine".