216807973 has 4 divisors (see below), whose sum is σ = 224284140. Its totient is φ = 209331808.

The previous prime is 216807967. The next prime is 216807977. The reversal of 216807973 is 379708612.

It is a happy number.

216807973 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 78110244 + 138697729 = 8838^2 + 11777^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-216807973 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216807977) 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, 3738040 + ... + 3738097.

It is an arithmetic number, because the mean of its divisors is an integer number (56071035).

Almost surely, 2^216807973 is an apocalyptic number.

It is an amenable number.

216807973 is a deficient number, since it is larger than the sum of its proper divisors (7476167).

216807973 is an equidigital number, since it uses as much as digits as its factorization.

216807973 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7476166.

The product of its (nonzero) digits is 127008, while the sum is 43.

The square root of 216807973 is about 14724.4005990057. The cubic root of 216807973 is about 600.7471922681.

The spelling of 216807973 in words is "two hundred sixteen million, eight hundred seven thousand, nine hundred seventy-three".