19722161 has 2 divisors, whose sum is σ = 19722162. Its totient is φ = 19722160.

The previous prime is 19722149. The next prime is 19722163. The reversal of 19722161 is 16122791.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19536400 + 185761 = 4420^2 + 431^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19722161 is a prime.

Together with 19722163, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (19722163) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9861080 + 9861081.

It is an arithmetic number, because the mean of its divisors is an integer number (9861081).

Almost surely, 2^19722161 is an apocalyptic number.

It is an amenable number.

19722161 is a deficient number, since it is larger than the sum of its proper divisors (1).

19722161 is an equidigital number, since it uses as much as digits as its factorization.

19722161 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1512, while the sum is 29.

The square root of 19722161 is about 4440.9639719322. The cubic root of 19722161 is about 270.1789440205.

The spelling of 19722161 in words is "nineteen million, seven hundred twenty-two thousand, one hundred sixty-one".