72115522121 has 2 divisors, whose sum is σ = 72115522122. Its totient is φ = 72115522120.

The previous prime is 72115522103. The next prime is 72115522133. The reversal of 72115522121 is 12122551127.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 67787329600 + 4328192521 = 260360^2 + 65789^2 .

It is an emirp because it is prime and its reverse (12122551127) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-72115522121 is a prime.

It is not a weakly prime, because it can be changed into another prime (72015522121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36057761060 + 36057761061.

It is an arithmetic number, because the mean of its divisors is an integer number (36057761061).

Almost surely, 2^72115522121 is an apocalyptic number.

It is an amenable number.

72115522121 is a deficient number, since it is larger than the sum of its proper divisors (1).

72115522121 is an equidigital number, since it uses as much as digits as its factorization.

72115522121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2800, while the sum is 29.

The spelling of 72115522121 in words is "seventy-two billion, one hundred fifteen million, five hundred twenty-two thousand, one hundred twenty-one".