20499990221 has 2 divisors, whose sum is σ = 20499990222. Its totient is φ = 20499990220.

The previous prime is 20499990197. The next prime is 20499990289. The reversal of 20499990221 is 12209999402.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20411836900 + 88153321 = 142870^2 + 9389^2 .

It is a cyclic number.

It is not a de Polignac number, because 20499990221 - 2⁶ = 20499990157 is a prime.

It is a super-2 number, since 2×20499990221² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20499993221) 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, 10249995110 + 10249995111.

It is an arithmetic number, because the mean of its divisors is an integer number (10249995111).

Almost surely, 2^20499990221 is an apocalyptic number.

It is an amenable number.

20499990221 is a deficient number, since it is larger than the sum of its proper divisors (1).

20499990221 is an equidigital number, since it uses as much as digits as its factorization.

20499990221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 209952, while the sum is 47.

The spelling of 20499990221 in words is "twenty billion, four hundred ninety-nine million, nine hundred ninety thousand, two hundred twenty-one".