221501770161 has 12 divisors (see below), whose sum is σ = 343553766192. Its totient is φ = 126572440008.

The previous prime is 221501770129. The next prime is 221501770211. The reversal of 221501770161 is 161077105122.

It is not a de Polignac number, because 221501770161 - 2⁵ = 221501770129 is a prime.

It is not an unprimeable number, because it can be changed into a prime (221501770261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 753407235 + ... + 753407528.

It is an arithmetic number, because the mean of its divisors is an integer number (28629480516).

Almost surely, 2^221501770161 is an apocalyptic number.

221501770161 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

221501770161 is a deficient number, since it is larger than the sum of its proper divisors (122051996031).

221501770161 is a wasteful number, since it uses less digits than its factorization.

221501770161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1506814780 (or 1506814773 counting only the distinct ones).

The product of its (nonzero) digits is 5880, while the sum is 33.

Adding to 221501770161 its reverse (161077105122), we get a palindrome (382578875283).

The spelling of 221501770161 in words is "two hundred twenty-one billion, five hundred one million, seven hundred seventy thousand, one hundred sixty-one".