7216805 has 8 divisors (see below), whose sum is σ = 8683800. Its totient is φ = 5757696.

The previous prime is 7216801. The next prime is 7216837. The reversal of 7216805 is 5086127.

7216805 = 1550² + 1551² + 1552².

It can be written as a sum of positive squares in 4 ways, for example, as 749956 + 6466849 = 866^2 + 2543^2 .

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 7216805 - 2² = 7216801 is a prime.

It is an Ulam number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7216801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 281 + ... + 3809.

It is an arithmetic number, because the mean of its divisors is an integer number (1085475).

Almost surely, 2^7216805 is an apocalyptic number.

It is an amenable number.

7216805 is a deficient number, since it is larger than the sum of its proper divisors (1466995).

7216805 is a wasteful number, since it uses less digits than its factorization.

7216805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3943.

The product of its (nonzero) digits is 3360, while the sum is 29.

The square root of 7216805 is about 2686.4111747832. The cubic root of 7216805 is about 193.2479921268.

The spelling of 7216805 in words is "seven million, two hundred sixteen thousand, eight hundred five".