721563 has 8 divisors (see below), whose sum is σ = 1012800. Its totient is φ = 455688.

The previous prime is 721561. The next prime is 721571. The reversal of 721563 is 365127.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 721563 - 2¹ = 721561 is a prime.

It is not an unprimeable number, because it can be changed into a prime (721561) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6273 + ... + 6386.

It is an arithmetic number, because the mean of its divisors is an integer number (126600).

2⁷²¹⁵⁶³ is an apocalyptic number.

721563 is a deficient number, since it is larger than the sum of its proper divisors (291237).

721563 is a wasteful number, since it uses less digits than its factorization.

721563 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12681.

The product of its digits is 1260, while the sum is 24.

The square root of 721563 is about 849.4486447102. The cubic root of 721563 is about 89.6929039426.

The spelling of 721563 in words is "seven hundred twenty-one thousand, five hundred sixty-three".