720331221 has 32 divisors (see below), whose sum is σ = 1010114560. Its totient is φ = 456062400.

The previous prime is 720331189. The next prime is 720331231. The reversal of 720331221 is 122133027.

It is not a de Polignac number, because 720331221 - 2⁵ = 720331189 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 (720331231) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1331211 + ... + 1331751.

It is an arithmetic number, because the mean of its divisors is an integer number (31566080).

Almost surely, 2^720331221 is an apocalyptic number.

It is an amenable number.

720331221 is a deficient number, since it is larger than the sum of its proper divisors (289783339).

720331221 is a wasteful number, since it uses less digits than its factorization.

720331221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 817.

The product of its (nonzero) digits is 504, while the sum is 21.

The square root of 720331221 is about 26838.9869592725. The cubic root of 720331221 is about 896.4183667010.

Adding to 720331221 its reverse (122133027), we get a palindrome (842464248).

The spelling of 720331221 in words is "seven hundred twenty million, three hundred thirty-one thousand, two hundred twenty-one".