72111685 has 4 divisors (see below), whose sum is σ = 86534028. Its totient is φ = 57689344.

The previous prime is 72111659. The next prime is 72111691. The reversal of 72111685 is 58611127.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 58611127 = 79 ⋅741913.

It can be written as a sum of positive squares in 2 ways, for example, as 12173121 + 59938564 = 3489^2 + 7742^2 .

It is a cyclic number.

It is not a de Polignac number, because 72111685 - 2¹¹ = 72109637 is a prime.

It is a super-2 number, since 2×72111685² = 10400190227078450, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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, 7211164 + ... + 7211173.

It is an arithmetic number, because the mean of its divisors is an integer number (21633507).

Almost surely, 2^72111685 is an apocalyptic number.

It is an amenable number.

72111685 is a deficient number, since it is larger than the sum of its proper divisors (14422343).

72111685 is a wasteful number, since it uses less digits than its factorization.

72111685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14422342.

The product of its digits is 3360, while the sum is 31.

The square root of 72111685 is about 8491.8599258349. The cubic root of 72111685 is about 416.2317591889.

The spelling of 72111685 in words is "seventy-two million, one hundred eleven thousand, six hundred eighty-five".