221615161 has 2 divisors, whose sum is σ = 221615162. Its totient is φ = 221615160.

The previous prime is 221615159. The next prime is 221615167. The reversal of 221615161 is 161516122.

It is a happy number.

221615161 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 166023225 + 55591936 = 12885^2 + 7456^2 .

It is a cyclic number.

It is not a de Polignac number, because 221615161 - 2¹ = 221615159 is a prime.

It is a super-2 number, since 2×221615161² = 98226559170111842, which contains 22 as substring.

Together with 221615159, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (221615167) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110807580 + 110807581.

It is an arithmetic number, because the mean of its divisors is an integer number (110807581).

Almost surely, 2^221615161 is an apocalyptic number.

It is an amenable number.

221615161 is a deficient number, since it is larger than the sum of its proper divisors (1).

221615161 is an equidigital number, since it uses as much as digits as its factorization.

221615161 is an evil number, because the sum of its binary digits is even.

The product of its digits is 720, while the sum is 25.

The square root of 221615161 is about 14886.7444728524. The cubic root of 221615161 is about 605.1548095513.

The spelling of 221615161 in words is "two hundred twenty-one million, six hundred fifteen thousand, one hundred sixty-one".