7216813 has 4 divisors (see below), whose sum is σ = 7411900. Its totient is φ = 7021728.

The previous prime is 7216801. The next prime is 7216837. The reversal of 7216813 is 3186127.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3541924 + 3674889 = 1882^2 + 1917^2 .

It is a cyclic number.

It is not a de Polignac number, because 7216813 - 2⁹ = 7216301 is a prime.

It is an Ulam number.

It is a Duffinian number.

7216813 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7216213) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 97488 + ... + 97561.

It is an arithmetic number, because the mean of its divisors is an integer number (1852975).

Almost surely, 2^7216813 is an apocalyptic number.

It is an amenable number.

7216813 is a deficient number, since it is larger than the sum of its proper divisors (195087).

7216813 is a wasteful number, since it uses less digits than its factorization.

7216813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 195086.

The product of its digits is 2016, while the sum is 28.

The square root of 7216813 is about 2686.4126637581. The cubic root of 7216813 is about 193.2480635334.

The spelling of 7216813 in words is "seven million, two hundred sixteen thousand, eight hundred thirteen".