720333221 has 4 divisors (see below), whose sum is σ = 723136332. Its totient is φ = 717530112.

The previous prime is 720333209. The next prime is 720333239. The reversal of 720333221 is 122333027.

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 478996996 + 241336225 = 21886^2 + 15535^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-720333221 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 (720333241) 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, 1401170 + ... + 1401683.

It is an arithmetic number, because the mean of its divisors is an integer number (180784083).

Almost surely, 2^720333221 is an apocalyptic number.

It is an amenable number.

720333221 is a deficient number, since it is larger than the sum of its proper divisors (2803111).

720333221 is a wasteful number, since it uses less digits than its factorization.

720333221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2803110.

The product of its (nonzero) digits is 1512, while the sum is 23.

The square root of 720333221 is about 26839.0242184771. The cubic root of 720333221 is about 896.4191963356.

Adding to 720333221 its reverse (122333027), we get a palindrome (842666248).

The spelling of 720333221 in words is "seven hundred twenty million, three hundred thirty-three thousand, two hundred twenty-one".