721705210893 has 18 divisors (see below), whose sum is σ = 1065115093614. Its totient is φ = 470899840944.

The previous prime is 721705210829. The next prime is 721705210909. The reversal of 721705210893 is 398012507127.

It can be written as a sum of positive squares in only one way, i.e., 627482611044 + 94222599849 = 792138^2 + 306957^2 .

It is not a de Polignac number, because 721705210893 - 2⁶ = 721705210829 is a prime.

It is a super-2 number, since 2×721705210893² (a number of 25 digits) contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721705210813) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 18130746 + ... + 18170507.

Almost surely, 2^721705210893 is an apocalyptic number.

It is an amenable number.

721705210893 is a deficient number, since it is larger than the sum of its proper divisors (343409882721).

721705210893 is a wasteful number, since it uses less digits than its factorization.

721705210893 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36301353 (or 36301303 counting only the distinct ones).

The product of its (nonzero) digits is 211680, while the sum is 45.

The spelling of 721705210893 in words is "seven hundred twenty-one billion, seven hundred five million, two hundred ten thousand, eight hundred ninety-three".