721679 has 8 divisors (see below), whose sum is σ = 832128. Its totient is φ = 613080.

The previous prime is 721663. The next prime is 721687. The reversal of 721679 is 976127.

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

It is not a de Polignac number, because 721679 - 2⁴ = 721663 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 (721619) 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, 524 + ... + 1310.

It is an arithmetic number, because the mean of its divisors is an integer number (104016).

2⁷²¹⁶⁷⁹ is an apocalyptic number.

721679 is a deficient number, since it is larger than the sum of its proper divisors (110449).

721679 is a wasteful number, since it uses less digits than its factorization.

721679 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 925.

The product of its digits is 5292, while the sum is 32.

The square root of 721679 is about 849.5169215501. The cubic root of 721679 is about 89.6977100923.

The spelling of 721679 in words is "seven hundred twenty-one thousand, six hundred seventy-nine".