216621065 has 16 divisors (see below), whose sum is σ = 265020240. Its totient is φ = 169931520.

The previous prime is 216621029. The next prime is 216621101. The reversal of 216621065 is 560126612.

It is an interprime number because it is at equal distance from previous prime (216621029) and next prime (216621101).

It can be written as a sum of positive squares in 8 ways, for example, as 30976 + 216590089 = 176^2 + 14717^2 .

It is not a de Polignac number, because 216621065 - 2⁶ = 216621001 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 120191 + ... + 121979.

It is an arithmetic number, because the mean of its divisors is an integer number (16563765).

Almost surely, 2^216621065 is an apocalyptic number.

It is an amenable number.

216621065 is a deficient number, since it is larger than the sum of its proper divisors (48399175).

216621065 is a wasteful number, since it uses less digits than its factorization.

216621065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2252.

The product of its (nonzero) digits is 4320, while the sum is 29.

The square root of 216621065 is about 14718.0523507698. The cubic root of 216621065 is about 600.5745099069.

Adding to 216621065 its reverse (560126612), we get a palindrome (776747677).

The spelling of 216621065 in words is "two hundred sixteen million, six hundred twenty-one thousand, sixty-five".