115656166221 has 4 divisors (see below), whose sum is σ = 154208221632. Its totient is φ = 77104110812.

The previous prime is 115656166211. The next prime is 115656166237. The reversal of 115656166221 is 122661656511.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 122661656511 = 3 ⋅40887218837.

It is a cyclic number.

It is not a de Polignac number, because 115656166221 - 2⁵ = 115656166189 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (115656166211) 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, 19276027701 + ... + 19276027706.

It is an arithmetic number, because the mean of its divisors is an integer number (38552055408).

Almost surely, 2^115656166221 is an apocalyptic number.

It is an amenable number.

115656166221 is a deficient number, since it is larger than the sum of its proper divisors (38552055411).

115656166221 is an equidigital number, since it uses as much as digits as its factorization.

115656166221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38552055410.

The product of its digits is 129600, while the sum is 42.

The spelling of 115656166221 in words is "one hundred fifteen billion, six hundred fifty-six million, one hundred sixty-six thousand, two hundred twenty-one".