9942721 has 2 divisors, whose sum is σ = 9942722. Its totient is φ = 9942720.

The previous prime is 9942707. The next prime is 9942727. The reversal of 9942721 is 1272499.

It is a happy number.

9942721 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., 9363600 + 579121 = 3060^2 + 761^2 .

It is a cyclic number.

It is not a de Polignac number, because 9942721 - 2⁵ = 9942689 is a prime.

It is not a weakly prime, because it can be changed into another prime (9942727) 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, 4971360 + 4971361.

It is an arithmetic number, because the mean of its divisors is an integer number (4971361).

Almost surely, 2^9942721 is an apocalyptic number.

It is an amenable number.

9942721 is a deficient number, since it is larger than the sum of its proper divisors (1).

9942721 is an equidigital number, since it uses as much as digits as its factorization.

9942721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9072, while the sum is 34.

The square root of 9942721 is about 3153.2080489559. The cubic root of 9942721 is about 215.0313348957.

The spelling of 9942721 in words is "nine million, nine hundred forty-two thousand, seven hundred twenty-one".