72166748161 has 8 divisors (see below), whose sum is σ = 78477036840. Its totient is φ = 66085924608.

The previous prime is 72166748141. The next prime is 72166748177. The reversal of 72166748161 is 16184766127.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 49264465936 + 22902282225 = 221956^2 + 151335^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 72166748161 - 2⁷ = 72166748033 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72166748141) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 57365626 + ... + 57366883.

It is an arithmetic number, because the mean of its divisors is an integer number (9809629605).

Almost surely, 2^72166748161 is an apocalyptic number.

It is an amenable number.

72166748161 is a deficient number, since it is larger than the sum of its proper divisors (6310288679).

72166748161 is a wasteful number, since it uses less digits than its factorization.

72166748161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 114732563.

The product of its digits is 677376, while the sum is 49.

The spelling of 72166748161 in words is "seventy-two billion, one hundred sixty-six million, seven hundred forty-eight thousand, one hundred sixty-one".