221717202051 has 4 divisors (see below), whose sum is σ = 295622936072. Its totient is φ = 147811468032.

The previous prime is 221717202023. The next prime is 221717202143. The reversal of 221717202051 is 150202717122.

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

It is not a de Polignac number, because 221717202051 - 2⁹ = 221717201539 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221717702051) 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, 36952867006 + ... + 36952867011.

It is an arithmetic number, because the mean of its divisors is an integer number (73905734018).

Almost surely, 2^221717202051 is an apocalyptic number.

221717202051 is a deficient number, since it is larger than the sum of its proper divisors (73905734021).

221717202051 is an equidigital number, since it uses as much as digits as its factorization.

221717202051 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73905734020.

The product of its (nonzero) digits is 3920, while the sum is 30.

Adding to 221717202051 its reverse (150202717122), we get a palindrome (371919919173).

The spelling of 221717202051 in words is "two hundred twenty-one billion, seven hundred seventeen million, two hundred two thousand, fifty-one".