722721 has 16 divisors (see below), whose sum is σ = 1050624. Its totient is φ = 440064.

The previous prime is 722713. The next prime is 722723. The reversal of 722721 is 127227.

It is not a de Polignac number, because 722721 - 2³ = 722713 is a prime.

It is a Curzon number.

722721 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (722723) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1696 + ... + 2078.

It is an arithmetic number, because the mean of its divisors is an integer number (65664).

2⁷²²⁷²¹ is an apocalyptic number.

It is an amenable number.

722721 is a deficient number, since it is larger than the sum of its proper divisors (327903).

722721 is a wasteful number, since it uses less digits than its factorization.

722721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 440.

The product of its digits is 392, while the sum is 21.

The square root of 722721 is about 850.1299900603. The cubic root of 722721 is about 89.7408595011.

Adding to 722721 its reverse (127227), we get a palindrome (849948).

The spelling of 722721 in words is "seven hundred twenty-two thousand, seven hundred twenty-one", and thus it is an iban number.