721689073 has 8 divisors (see below), whose sum is σ = 827153600. Its totient is φ = 616816080.

The previous prime is 721689047. The next prime is 721689113. The reversal of 721689073 is 370986127.

It is a happy number.

721689073 is nontrivially palindromic in base 12.

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

It is a cyclic number.

It is not a de Polignac number, because 721689073 - 2¹³ = 721680881 is a prime.

It is not an unprimeable number, because it can be changed into a prime (721689043) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 145263 + ... + 150148.

It is an arithmetic number, because the mean of its divisors is an integer number (103394200).

Almost surely, 2^721689073 is an apocalyptic number.

It is an amenable number.

721689073 is a deficient number, since it is larger than the sum of its proper divisors (105464527).

721689073 is a wasteful number, since it uses less digits than its factorization.

721689073 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 295767.

The product of its (nonzero) digits is 127008, while the sum is 43.

The square root of 721689073 is about 26864.2713096782. The cubic root of 721689073 is about 896.9812741578.

The spelling of 721689073 in words is "seven hundred twenty-one million, six hundred eighty-nine thousand, seventy-three".