216710881 has 8 divisors (see below), whose sum is σ = 225063720. Its totient is φ = 208416768.

The previous prime is 216710873. The next prime is 216710891. The reversal of 216710881 is 188017612.

It can be written as a sum of positive squares in 4 ways, for example, as 132365025 + 84345856 = 11505^2 + 9184^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 216710881 - 2³ = 216710873 is a prime.

It is a super-2 number, since 2×216710881² = 93927211887592322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216710831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7086 + ... + 21991.

It is an arithmetic number, because the mean of its divisors is an integer number (28132965).

Almost surely, 2^216710881 is an apocalyptic number.

It is an amenable number.

216710881 is a deficient number, since it is larger than the sum of its proper divisors (8352839).

216710881 is a wasteful number, since it uses less digits than its factorization.

216710881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29363.

The product of its (nonzero) digits is 5376, while the sum is 34.

The square root of 216710881 is about 14721.1032534929. The cubic root of 216710881 is about 600.6575023693.

The spelling of 216710881 in words is "two hundred sixteen million, seven hundred ten thousand, eight hundred eighty-one".