20097221 has 2 divisors, whose sum is σ = 20097222. Its totient is φ = 20097220.

The previous prime is 20097197. The next prime is 20097223. The reversal of 20097221 is 12279002.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15124321 + 4972900 = 3889^2 + 2230^2 .

It is a cyclic number.

It is not a de Polignac number, because 20097221 - 2⁶ = 20097157 is a prime.

Together with 20097223, it forms a pair of twin primes.

It is a Chen prime.

It is equal to p_1276421 and since 20097221 and 1276421 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20097223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10048610 + 10048611.

It is an arithmetic number, because the mean of its divisors is an integer number (10048611).

Almost surely, 2^20097221 is an apocalyptic number.

It is an amenable number.

20097221 is a deficient number, since it is larger than the sum of its proper divisors (1).

20097221 is an equidigital number, since it uses as much as digits as its factorization.

20097221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 504, while the sum is 23.

The square root of 20097221 is about 4482.9924157866. The cubic root of 20097221 is about 271.8808815568.

The spelling of 20097221 in words is "twenty million, ninety-seven thousand, two hundred twenty-one".