721732 has 24 divisors (see below), whose sum is σ = 1411200. Its totient is φ = 320160.

The previous prime is 721709. The next prime is 721733. The reversal of 721732 is 237127.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is not an unprimeable number, because it can be changed into a prime (721733) by changing a digit.

721732 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 7 ways as a sum of consecutive naturals, for example, 1894 + ... + 2242.

It is an arithmetic number, because the mean of its divisors is an integer number (58800).

2⁷²¹⁷³² is an apocalyptic number.

It is an amenable number.

721732 is a deficient number, since it is larger than the sum of its proper divisors (689468).

721732 is a wasteful number, since it uses less digits than its factorization.

721732 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 411 (or 409 counting only the distinct ones).

The product of its digits is 588, while the sum is 22.

The square root of 721732 is about 849.5481151765. The cubic root of 721732 is about 89.6999058341.

Adding to 721732 its reverse (237127), we get a palindrome (958859).

The spelling of 721732 in words is "seven hundred twenty-one thousand, seven hundred thirty-two".