161016221 has 2 divisors, whose sum is σ = 161016222. Its totient is φ = 161016220.

The previous prime is 161016199. The next prime is 161016259. The reversal of 161016221 is 122610161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 102799321 + 58216900 = 10139^2 + 7630^2 .

It is a cyclic number.

It is not a de Polignac number, because 161016221 - 2⁶ = 161016157 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 161016193 and 161016202.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161016521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80508110 + 80508111.

It is an arithmetic number, because the mean of its divisors is an integer number (80508111).

Almost surely, 2^161016221 is an apocalyptic number.

It is an amenable number.

161016221 is a deficient number, since it is larger than the sum of its proper divisors (1).

161016221 is an equidigital number, since it uses as much as digits as its factorization.

161016221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 144, while the sum is 20.

The square root of 161016221 is about 12689.2167212953. The cubic root of 161016221 is about 544.0304519520.

Adding to 161016221 its reverse (122610161), we get a palindrome (283626382).

It can be divided in two parts, 16101 and 6221, that added together give a palindrome (22322).

The spelling of 161016221 in words is "one hundred sixty-one million, sixteen thousand, two hundred twenty-one".