721683 has 8 divisors (see below), whose sum is σ = 1069200. Its totient is φ = 481104.

The previous prime is 721663. The next prime is 721687. The reversal of 721683 is 386127.

It is not a de Polignac number, because 721683 - 2⁶ = 721619 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 26729 = 721683 / (7 + 2 + 1 + 6 + 8 + 3).

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 721683.

It is not an unprimeable number, because it can be changed into a prime (721687) 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, 13338 + ... + 13391.

It is an arithmetic number, because the mean of its divisors is an integer number (133650).

2⁷²¹⁶⁸³ is an apocalyptic number.

721683 is a deficient number, since it is larger than the sum of its proper divisors (347517).

721683 is a wasteful number, since it uses less digits than its factorization.

721683 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26738 (or 26732 counting only the distinct ones).

The product of its digits is 2016, while the sum is 27.

The square root of 721683 is about 849.5192758260. The cubic root of 721683 is about 89.6978758124.

The spelling of 721683 in words is "seven hundred twenty-one thousand, six hundred eighty-three".