721673771858 has 16 divisors (see below), whose sum is σ = 1165878692160. Its totient is φ = 333052207056.

The previous prime is 721673771857. The next prime is 721673771887. The reversal of 721673771858 is 858177376127.

It is a Smith number, since the sum of its digits (62) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 721673771858.

It is not an unprimeable number, because it can be changed into a prime (721673771857) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 849560 + ... + 1471427.

It is an arithmetic number, because the mean of its divisors is an integer number (72867418260).

Almost surely, 2^721673771858 is an apocalyptic number.

721673771858 is a deficient number, since it is larger than the sum of its proper divisors (444204920302).

721673771858 is a wasteful number, since it uses less digits than its factorization.

721673771858 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2332961.

The product of its digits is 27659520, while the sum is 62.

The spelling of 721673771858 in words is "seven hundred twenty-one billion, six hundred seventy-three million, seven hundred seventy-one thousand, eight hundred fifty-eight".