16111332221 has 2 divisors, whose sum is σ = 16111332222. Its totient is φ = 16111332220.

The previous prime is 16111332197. The next prime is 16111332229. The reversal of 16111332221 is 12223311161.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14379607225 + 1731724996 = 119915^2 + 41614^2 .

It is a cyclic number.

It is not a de Polignac number, because 16111332221 - 2¹⁸ = 16111070077 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16111332229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8055666110 + 8055666111.

It is an arithmetic number, because the mean of its divisors is an integer number (8055666111).

Almost surely, 2^16111332221 is an apocalyptic number.

It is an amenable number.

16111332221 is a deficient number, since it is larger than the sum of its proper divisors (1).

16111332221 is an equidigital number, since it uses as much as digits as its factorization.

16111332221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 432, while the sum is 23.

Adding to 16111332221 its reverse (12223311161), we get a palindrome (28334643382).

The spelling of 16111332221 in words is "sixteen billion, one hundred eleven million, three hundred thirty-two thousand, two hundred twenty-one".