673855991991 has 64 divisors (see below), whose sum is σ = 1228910269440. Its totient is φ = 355374864000.

The previous prime is 673855991969. The next prime is 673855991999. The reversal of 673855991991 is 199199558376.

673855991991 is a `hidden beast` number, since 6 + 7 + 385 + 59 + 9 + 199 + 1 = 666.

It is not a de Polignac number, because 673855991991 - 2¹⁴ = 673855975607 is a prime.

It is a super-2 number, since 2×673855991991² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (673855991999) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 15120241 + ... + 15164741.

It is an arithmetic number, because the mean of its divisors is an integer number (19201722960).

Almost surely, 2^673855991991 is an apocalyptic number.

673855991991 is a deficient number, since it is larger than the sum of its proper divisors (555054277449).

673855991991 is a wasteful number, since it uses less digits than its factorization.

673855991991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50693 (or 50687 counting only the distinct ones).

The product of its digits is 165337200, while the sum is 72.

The spelling of 673855991991 in words is "six hundred seventy-three billion, eight hundred fifty-five million, nine hundred ninety-one thousand, nine hundred ninety-one".