9400021 has 2 divisors, whose sum is σ = 9400022. Its totient is φ = 9400020.

The previous prime is 9400019. The next prime is 9400043. The reversal of 9400021 is 1200049.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8820900 + 579121 = 2970^2 + 761^2 .

It is a cyclic number.

It is not a de Polignac number, because 9400021 - 2¹ = 9400019 is a prime.

Together with 9400019, it forms a pair of twin primes.

9400021 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 9399968 and 9400004.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9400121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4700010 + 4700011.

It is an arithmetic number, because the mean of its divisors is an integer number (4700011).

Almost surely, 2^9400021 is an apocalyptic number.

It is an amenable number.

9400021 is a deficient number, since it is larger than the sum of its proper divisors (1).

9400021 is an equidigital number, since it uses as much as digits as its factorization.

9400021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 9400021 is about 3065.9453680716. The cubic root of 9400021 is about 211.0455866104.

The spelling of 9400021 in words is "nine million, four hundred thousand, twenty-one".