721559 has 4 divisors (see below), whose sum is σ = 739200. Its totient is φ = 703920.

The previous prime is 721547. The next prime is 721561. The reversal of 721559 is 955127.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 721559 - 2¹² = 717463 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 (721529) 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, 8759 + ... + 8840.

It is an arithmetic number, because the mean of its divisors is an integer number (184800).

2⁷²¹⁵⁵⁹ is an apocalyptic number.

721559 is a deficient number, since it is larger than the sum of its proper divisors (17641).

721559 is a wasteful number, since it uses less digits than its factorization.

721559 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17640.

The product of its digits is 3150, while the sum is 29.

The square root of 721559 is about 849.4462902385. The cubic root of 721559 is about 89.6927382041.

The spelling of 721559 in words is "seven hundred twenty-one thousand, five hundred fifty-nine".