721422 has 24 divisors (see below), whose sum is σ = 1683864. Its totient is φ = 221904.

The previous prime is 721397. The next prime is 721439. The reversal of 721422 is 224127.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 721395 and 721404.

It is a congruent number.

It is an unprimeable number.

721422 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1308 + ... + 1775.

It is an arithmetic number, because the mean of its divisors is an integer number (70161).

2⁷²¹⁴²² is an apocalyptic number.

721422 is an abundant number, since it is smaller than the sum of its proper divisors (962442).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

721422 is a wasteful number, since it uses less digits than its factorization.

721422 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3104 (or 3101 counting only the distinct ones).

The product of its digits is 224, while the sum is 18.

The square root of 721422 is about 849.3656456439. The cubic root of 721422 is about 89.6870612911.

Adding to 721422 its reverse (224127), we get a palindrome (945549).

The spelling of 721422 in words is "seven hundred twenty-one thousand, four hundred twenty-two", and thus it is an iban number.