9842121221 has 2 divisors, whose sum is σ = 9842121222. Its totient is φ = 9842121220.

The previous prime is 9842121193. The next prime is 9842121229. The reversal of 9842121221 is 1221212489.

9842121221 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8729164900 + 1112956321 = 93430^2 + 33361^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-9842121221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9842121229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4921060610 + 4921060611.

It is an arithmetic number, because the mean of its divisors is an integer number (4921060611).

Almost surely, 2^9842121221 is an apocalyptic number.

It is an amenable number.

9842121221 is a deficient number, since it is larger than the sum of its proper divisors (1).

9842121221 is an equidigital number, since it uses as much as digits as its factorization.

9842121221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4608, while the sum is 32.

The square root of 9842121221 is about 99207.4655507336. The cubic root of 9842121221 is about 2143.0365096002.

The spelling of 9842121221 in words is "nine billion, eight hundred forty-two million, one hundred twenty-one thousand, two hundred twenty-one".