722222221 has 24 divisors (see below), whose sum is σ = 873331200. Its totient is φ = 594871200.

The previous prime is 722222213. The next prime is 722222227. The reversal of 722222221 is 122222227.

It is not a de Polignac number, because 722222221 - 2³ = 722222213 is a prime.

It is a nialpdrome in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 722222192 and 722222201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (722222227) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 224736 + ... + 227926.

It is an arithmetic number, because the mean of its divisors is an integer number (36388800).

Almost surely, 2^722222221 is an apocalyptic number.

It is an amenable number.

722222221 is a deficient number, since it is larger than the sum of its proper divisors (151108979).

722222221 is a wasteful number, since it uses less digits than its factorization.

722222221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3385 (or 3378 counting only the distinct ones).

The product of its digits is 896, while the sum is 22.

The square root of 722222221 is about 26874.1924715888. The cubic root of 722222221 is about 897.2021015084.

Adding to 722222221 its reverse (122222227), we get a palindrome (844444448).

The spelling of 722222221 in words is "seven hundred twenty-two million, two hundred twenty-two thousand, two hundred twenty-one".