11155166221 has 4 divisors (see below), whose sum is σ = 11640173472. Its totient is φ = 10670158972.

The previous prime is 11155166213. The next prime is 11155166237. The reversal of 11155166221 is 12266155111.

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.

It is a cyclic number.

It is not a de Polignac number, because 11155166221 - 2³ = 11155166213 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 (11155166021) 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, 242503591 + ... + 242503636.

It is an arithmetic number, because the mean of its divisors is an integer number (2910043368).

Almost surely, 2^11155166221 is an apocalyptic number.

It is an amenable number.

11155166221 is a deficient number, since it is larger than the sum of its proper divisors (485007251).

11155166221 is an equidigital number, since it uses as much as digits as its factorization.

11155166221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 485007250.

The product of its digits is 3600, while the sum is 31.

The spelling of 11155166221 in words is "eleven billion, one hundred fifty-five million, one hundred sixty-six thousand, two hundred twenty-one".