221132171809 has 4 divisors (see below), whose sum is σ = 224161379716. Its totient is φ = 218102963904.

The previous prime is 221132171807. The next prime is 221132171851. The reversal of 221132171809 is 908171231122.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 150998302225 + 70133869584 = 388585^2 + 264828^2 .

It is a cyclic number.

It is not a de Polignac number, because 221132171809 - 2¹ = 221132171807 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221132171803) 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, 1514603844 + ... + 1514603989.

It is an arithmetic number, because the mean of its divisors is an integer number (56040344929).

Almost surely, 2^221132171809 is an apocalyptic number.

It is an amenable number.

221132171809 is a deficient number, since it is larger than the sum of its proper divisors (3029207907).

221132171809 is an equidigital number, since it uses as much as digits as its factorization.

221132171809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3029207906.

The product of its (nonzero) digits is 12096, while the sum is 37.

It can be divided in two parts, 221132 and 171809, that added together give a triangular number (392941 = T₈₈₆).

The spelling of 221132171809 in words is "two hundred twenty-one billion, one hundred thirty-two million, one hundred seventy-one thousand, eight hundred nine".