221688720171 has 6 divisors (see below), whose sum is σ = 320217040260. Its totient is φ = 147792480108.

The previous prime is 221688720151. The next prime is 221688720191. The reversal of 221688720171 is 171027886122.

It is an interprime number because it is at equal distance from previous prime (221688720151) and next prime (221688720191).

It is not a de Polignac number, because 221688720171 - 2⁵ = 221688720139 is a prime.

It is not an unprimeable number, because it can be changed into a prime (221688720151) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 12316040001 + ... + 12316040018.

It is an arithmetic number, because the mean of its divisors is an integer number (53369506710).

Almost surely, 2^221688720171 is an apocalyptic number.

221688720171 is a deficient number, since it is larger than the sum of its proper divisors (98528320089).

221688720171 is a wasteful number, since it uses less digits than its factorization.

221688720171 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24632080025 (or 24632080022 counting only the distinct ones).

The product of its (nonzero) digits is 150528, while the sum is 45.

The spelling of 221688720171 in words is "two hundred twenty-one billion, six hundred eighty-eight million, seven hundred twenty thousand, one hundred seventy-one".