11523978197 has 4 divisors (see below), whose sum is σ = 11558174316. Its totient is φ = 11489782080.

The previous prime is 11523978073. The next prime is 11523978229. The reversal of 11523978197 is 79187932511.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 79187932511 = 60943 ⋅1299377.

It can be written as a sum of positive squares in 2 ways, for example, as 1404825361 + 10119152836 = 37481^2 + 100594^2 .

It is a cyclic number.

It is not a de Polignac number, because 11523978197 - 2³⁰ = 10450236373 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11523978997) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17097554 + ... + 17098227.

It is an arithmetic number, because the mean of its divisors is an integer number (2889543579).

Almost surely, 2^11523978197 is an apocalyptic number.

It is an amenable number.

11523978197 is a deficient number, since it is larger than the sum of its proper divisors (34196119).

11523978197 is an equidigital number, since it uses as much as digits as its factorization.

11523978197 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34196118.

The product of its digits is 952560, while the sum is 53.

The spelling of 11523978197 in words is "eleven billion, five hundred twenty-three million, nine hundred seventy-eight thousand, one hundred ninety-seven".