721020201221 has 12 divisors (see below), whose sum is σ = 766003215360. Its totient is φ = 678540638400.

The previous prime is 721020201199. The next prime is 721020201227. The reversal of 721020201221 is 122102020127.

It is not a de Polignac number, because 721020201221 - 2⁶ = 721020201157 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 721020201193 and 721020201202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721020201227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2961020 + ... + 3195258.

It is an arithmetic number, because the mean of its divisors is an integer number (63833601280).

Almost surely, 2^721020201221 is an apocalyptic number.

It is an amenable number.

721020201221 is a deficient number, since it is larger than the sum of its proper divisors (44983014139).

721020201221 is a wasteful number, since it uses less digits than its factorization.

721020201221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 244924 (or 244907 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 20.

Adding to 721020201221 its reverse (122102020127), we get a palindrome (843122221348).

The spelling of 721020201221 in words is "seven hundred twenty-one billion, twenty million, two hundred one thousand, two hundred twenty-one".