21996197 has 2 divisors, whose sum is σ = 21996198. Its totient is φ = 21996196.

The previous prime is 21996187. The next prime is 21996199. The reversal of 21996197 is 79169912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21585316 + 410881 = 4646^2 + 641^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21996197 is a prime.

Together with 21996199, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21996199) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10998098 + 10998099.

It is an arithmetic number, because the mean of its divisors is an integer number (10998099).

Almost surely, 2^21996197 is an apocalyptic number.

It is an amenable number.

21996197 is a deficient number, since it is larger than the sum of its proper divisors (1).

21996197 is an equidigital number, since it uses as much as digits as its factorization.

21996197 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 61236, while the sum is 44.

The square root of 21996197 is about 4690.0103411400. The cubic root of 21996197 is about 280.1877864449.

The spelling of 21996197 in words is "twenty-one million, nine hundred ninety-six thousand, one hundred ninety-seven".