72173721171 has 32 divisors (see below), whose sum is σ = 101223198720. Its totient is φ = 45654185984.

The previous prime is 72173721167. The next prime is 72173721239. The reversal of 72173721171 is 17112737127.

It is not a de Polignac number, because 72173721171 - 2² = 72173721167 is a prime.

It is a super-2 number, since 2×72173721171² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (72173722171) 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 31 ways as a sum of consecutive naturals, for example, 21484990 + ... + 21488348.

It is an arithmetic number, because the mean of its divisors is an integer number (3163224960).

Almost surely, 2^72173721171 is an apocalyptic number.

72173721171 is a deficient number, since it is larger than the sum of its proper divisors (29049477549).

72173721171 is a wasteful number, since it uses less digits than its factorization.

72173721171 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5795.

The product of its digits is 28812, while the sum is 39.

The spelling of 72173721171 in words is "seventy-two billion, one hundred seventy-three million, seven hundred twenty-one thousand, one hundred seventy-one".