9901421 has 2 divisors, whose sum is σ = 9901422. Its totient is φ = 9901420.

The previous prime is 9901403. The next prime is 9901427. The reversal of 9901421 is 1241099.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8185321 + 1716100 = 2861^2 + 1310^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-9901421 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9901427) 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, 4950710 + 4950711.

It is an arithmetic number, because the mean of its divisors is an integer number (4950711).

Almost surely, 2^9901421 is an apocalyptic number.

It is an amenable number.

9901421 is a deficient number, since it is larger than the sum of its proper divisors (1).

9901421 is an equidigital number, since it uses as much as digits as its factorization.

9901421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 648, while the sum is 26.

The square root of 9901421 is about 3146.6523481313. The cubic root of 9901421 is about 214.7331898537.

The spelling of 9901421 in words is "nine million, nine hundred one thousand, four hundred twenty-one".