72112121 has 2 divisors, whose sum is σ = 72112122. Its totient is φ = 72112120.

The previous prime is 72112099. The next prime is 72112123. The reversal of 72112121 is 12121127.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 51681721 + 20430400 = 7189^2 + 4520^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-72112121 is a prime.

Together with 72112123, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 72112121.

It is not a weakly prime, because it can be changed into another prime (72112123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36056060 + 36056061.

It is an arithmetic number, because the mean of its divisors is an integer number (36056061).

Almost surely, 2^72112121 is an apocalyptic number.

It is an amenable number.

72112121 is a deficient number, since it is larger than the sum of its proper divisors (1).

72112121 is an equidigital number, since it uses as much as digits as its factorization.

72112121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 56, while the sum is 17.

The square root of 72112121 is about 8491.8855974395. The cubic root of 72112121 is about 416.2325980575.

Adding to 72112121 its reverse (12121127), we get a palindrome (84233248).

The spelling of 72112121 in words is "seventy-two million, one hundred twelve thousand, one hundred twenty-one".