216442945 has 8 divisors (see below), whose sum is σ = 263989800. Its totient is φ = 170315520.

The previous prime is 216442931. The next prime is 216442981. The reversal of 216442945 is 549244612.

It is a Cunningham number, because it is equal to 14712²+1.

It can be written as a sum of positive squares in 4 ways, for example, as 7033104 + 209409841 = 2652^2 + 14471^2 .

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

It is not a de Polignac number, because 216442945 - 2¹³ = 216434753 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 354520 + ... + 355129.

It is an arithmetic number, because the mean of its divisors is an integer number (32998725).

Almost surely, 2^216442945 is an apocalyptic number.

It is an amenable number.

216442945 is a deficient number, since it is larger than the sum of its proper divisors (47546855).

216442945 is an equidigital number, since it uses as much as digits as its factorization.

216442945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 709715.

The product of its digits is 69120, while the sum is 37.

The square root of 216442945 is about 14712.0000339859. Note that the first 4 decimals coincide. The cubic root of 216442945 is about 600.4098542280.

The spelling of 216442945 in words is "two hundred sixteen million, four hundred forty-two thousand, nine hundred forty-five".