721899 has 8 divisors (see below), whose sum is σ = 1069520. Its totient is φ = 481248.

The previous prime is 721891. The next prime is 721909. The reversal of 721899 is 998127.

It is a happy number.

It is not a de Polignac number, because 721899 - 2³ = 721891 is a prime.

It is a super-2 number, since 2×721899² = 1042276332402, which contains 22 as substring.

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 721899.

It is not an unprimeable number, because it can be changed into a prime (721891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13342 + ... + 13395.

It is an arithmetic number, because the mean of its divisors is an integer number (133690).

2⁷²¹⁸⁹⁹ is an apocalyptic number.

721899 is a deficient number, since it is larger than the sum of its proper divisors (347621).

721899 is a wasteful number, since it uses less digits than its factorization.

721899 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26746 (or 26740 counting only the distinct ones).

The product of its digits is 9072, while the sum is 36.

The square root of 721899 is about 849.6463970382. The cubic root of 721899 is about 89.7068237893.

The spelling of 721899 in words is "seven hundred twenty-one thousand, eight hundred ninety-nine".