721585715873 has 6 divisors (see below), whose sum is σ = 793147935762. Its totient is φ = 655987014320.

The previous prime is 721585715867. The next prime is 721585715909. The reversal of 721585715873 is 378517585127.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 651237702049 + 70348013824 = 806993^2 + 265232^2 .

It is a de Polignac number, because none of the positive numbers 2^k-721585715873 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (721585712873) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2981759036 + ... + 2981759277.

It is an arithmetic number, because the mean of its divisors is an integer number (132191322627).

Almost surely, 2^721585715873 is an apocalyptic number.

It is an amenable number.

721585715873 is a deficient number, since it is larger than the sum of its proper divisors (71562219889).

721585715873 is a wasteful number, since it uses less digits than its factorization.

721585715873 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5963518335 (or 5963518324 counting only the distinct ones).

The product of its digits is 16464000, while the sum is 59.

The spelling of 721585715873 in words is "seven hundred twenty-one billion, five hundred eighty-five million, seven hundred fifteen thousand, eight hundred seventy-three".