72171422173 has 2 divisors, whose sum is σ = 72171422174. Its totient is φ = 72171422172.

The previous prime is 72171422117. The next prime is 72171422177. The reversal of 72171422173 is 37122417127.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 67744116729 + 4427305444 = 260277^2 + 66538^2 .

It is a cyclic number.

It is not a de Polignac number, because 72171422173 - 2²⁵ = 72137867741 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72171422177) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36085711086 + 36085711087.

It is an arithmetic number, because the mean of its divisors is an integer number (36085711087).

Almost surely, 2^72171422173 is an apocalyptic number.

It is an amenable number.

72171422173 is a deficient number, since it is larger than the sum of its proper divisors (1).

72171422173 is an equidigital number, since it uses as much as digits as its factorization.

72171422173 is an evil number, because the sum of its binary digits is even.

The product of its digits is 32928, while the sum is 37.

The spelling of 72171422173 in words is "seventy-two billion, one hundred seventy-one million, four hundred twenty-two thousand, one hundred seventy-three".