216644445 has 12 divisors (see below), whose sum is σ = 375517116. Its totient is φ = 115543680.

The previous prime is 216644419. The next prime is 216644473. The reversal of 216644445 is 544446612.

216644445 is a `hidden beast` number, since 2 + 1 + 6 + 644 + 4 + 4 + 5 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 139854276 + 76790169 = 11826^2 + 8763^2 .

It is not a de Polignac number, because 216644445 - 2⁷ = 216644317 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2407116 + ... + 2407205.

It is an arithmetic number, because the mean of its divisors is an integer number (31293093).

Almost surely, 2^216644445 is an apocalyptic number.

It is an amenable number.

216644445 is a deficient number, since it is larger than the sum of its proper divisors (158872671).

216644445 is a wasteful number, since it uses less digits than its factorization.

216644445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4814332 (or 4814329 counting only the distinct ones).

The product of its digits is 92160, while the sum is 36.

The square root of 216644445 is about 14718.8465920397. The cubic root of 216644445 is about 600.5961158803.

It can be divided in two parts, 21 and 6644445, that added together give a palindrome (6644466).

The spelling of 216644445 in words is "two hundred sixteen million, six hundred forty-four thousand, four hundred forty-five".