21213221100161 has 2 divisors, whose sum is σ = 21213221100162. Its totient is φ = 21213221100160.

The previous prime is 21213221100103. The next prime is 21213221100163. The reversal of 21213221100161 is 16100112231212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18297596549761 + 2915624550400 = 4277569^2 + 1707520^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21213221100161 is a prime.

It is a Sophie Germain prime.

Together with 21213221100163, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21213221100163) 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 as a sum of consecutive naturals, namely, 10606610550080 + 10606610550081.

It is an arithmetic number, because the mean of its divisors is an integer number (10606610550081).

Almost surely, 2^{21213221100161} is an apocalyptic number.

It is an amenable number.

21213221100161 is a deficient number, since it is larger than the sum of its proper divisors (1).

21213221100161 is an equidigital number, since it uses as much as digits as its factorization.

21213221100161 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 288, while the sum is 23.

Adding to 21213221100161 its reverse (16100112231212), we get a palindrome (37313333331373).

The spelling of 21213221100161 in words is "twenty-one trillion, two hundred thirteen billion, two hundred twenty-one million, one hundred thousand, one hundred sixty-one".