721573 has 4 divisors (see below), whose sum is σ = 731808. Its totient is φ = 711340.

The previous prime is 721571. The next prime is 721577. The reversal of 721573 is 375127.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 721573 - 2¹ = 721571 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721571) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5011 + ... + 5152.

It is an arithmetic number, because the mean of its divisors is an integer number (182952).

2⁷²¹⁵⁷³ is an apocalyptic number.

It is an amenable number.

721573 is a deficient number, since it is larger than the sum of its proper divisors (10235).

721573 is a wasteful number, since it uses less digits than its factorization.

721573 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10234.

The product of its digits is 1470, while the sum is 25.

The square root of 721573 is about 849.4545308608. The cubic root of 721573 is about 89.6933182861.

The spelling of 721573 in words is "seven hundred twenty-one thousand, five hundred seventy-three".