721699 has 4 divisors (see below), whose sum is σ = 787320. Its totient is φ = 656080.

The previous prime is 721697. The next prime is 721703. The reversal of 721699 is 996127.

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 721699 - 2¹ = 721697 is a prime.

It is a Duffinian number.

721699 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (721697) 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, 32794 + ... + 32815.

It is an arithmetic number, because the mean of its divisors is an integer number (196830).

2⁷²¹⁶⁹⁹ is an apocalyptic number.

721699 is a deficient number, since it is larger than the sum of its proper divisors (65621).

721699 is a wasteful number, since it uses less digits than its factorization.

721699 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65620.

The product of its digits is 6804, while the sum is 34.

The square root of 721699 is about 849.5286928645. The cubic root of 721699 is about 89.6985386867.

It can be divided in two parts, 72 and 1699, that added together give a palindrome (1771).

The spelling of 721699 in words is "seven hundred twenty-one thousand, six hundred ninety-nine".