72111161 has 4 divisors (see below), whose sum is σ = 76353012. Its totient is φ = 67869312.

The previous prime is 72111103. The next prime is 72111163. The reversal of 72111161 is 16111127.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 36529936 + 35581225 = 6044^2 + 5965^2 .

It is a cyclic number.

It is not a de Polignac number, because 72111161 - 2¹⁸ = 71849017 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72111163) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2120900 + ... + 2120933.

It is an arithmetic number, because the mean of its divisors is an integer number (19088253).

Almost surely, 2^72111161 is an apocalyptic number.

It is an amenable number.

72111161 is a deficient number, since it is larger than the sum of its proper divisors (4241851).

72111161 is a wasteful number, since it uses less digits than its factorization.

72111161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4241850.

The product of its digits is 84, while the sum is 20.

The square root of 72111161 is about 8491.8290727028. The cubic root of 72111161 is about 416.2307510029.

Adding to 72111161 its reverse (16111127), we get a palindrome (88222288).

The spelling of 72111161 in words is "seventy-two million, one hundred eleven thousand, one hundred sixty-one".