721492 has 12 divisors (see below), whose sum is σ = 1268820. Its totient is φ = 358976.

The previous prime is 721481. The next prime is 721499. The reversal of 721492 is 294127.

It can be written as a sum of positive squares in 2 ways, for example, as 75076 + 646416 = 274^2 + 804^2 .

It is an alternating number because its digits alternate between odd and even.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721499) by changing a digit.

721492 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 3 ways as a sum of consecutive naturals, for example, 984 + ... + 1552.

It is an arithmetic number, because the mean of its divisors is an integer number (105735).

2⁷²¹⁴⁹² is an apocalyptic number.

It is an amenable number.

721492 is a deficient number, since it is larger than the sum of its proper divisors (547328).

721492 is a wasteful number, since it uses less digits than its factorization.

721492 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 890 (or 888 counting only the distinct ones).

The product of its digits is 1008, while the sum is 25.

The square root of 721492 is about 849.4068518678. The cubic root of 721492 is about 89.6899619934.

Adding to 721492 its product of digits (1008), we get a square (722500 = 850²).

The spelling of 721492 in words is "seven hundred twenty-one thousand, four hundred ninety-two".