216969985 has 16 divisors (see below), whose sum is σ = 267639120. Its totient is φ = 168791040.

The previous prime is 216969983. The next prime is 216970049. The reversal of 216969985 is 589969612.

It is a happy number.

216969985 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 8 ways, for example, as 107474689 + 109495296 = 10367^2 + 10464^2 .

It is not a de Polignac number, because 216969985 - 2¹ = 216969983 is a prime.

It is not an unprimeable number, because it can be changed into a prime (216969983) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23149 + ... + 31141.

It is an arithmetic number, because the mean of its divisors is an integer number (16727445).

Almost surely, 2^216969985 is an apocalyptic number.

It is an amenable number.

216969985 is a deficient number, since it is larger than the sum of its proper divisors (50669135).

216969985 is an equidigital number, since it uses as much as digits as its factorization.

216969985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8148.

The product of its digits is 2099520, while the sum is 55.

The square root of 216969985 is about 14729.9010519419. The cubic root of 216969985 is about 600.8967931947.

The spelling of 216969985 in words is "two hundred sixteen million, nine hundred sixty-nine thousand, nine hundred eighty-five".