9943721 has 2 divisors, whose sum is σ = 9943722. Its totient is φ = 9943720.

The previous prime is 9943711. The next prime is 9943727. The reversal of 9943721 is 1273499.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5125696 + 4818025 = 2264^2 + 2195^2 .

It is an emirp because it is prime and its reverse (1273499) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 9943721 - 2¹⁰ = 9942697 is a prime.

It is not a weakly prime, because it can be changed into another prime (9943727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4971860 + 4971861.

It is an arithmetic number, because the mean of its divisors is an integer number (4971861).

Almost surely, 2^9943721 is an apocalyptic number.

It is an amenable number.

9943721 is a deficient number, since it is larger than the sum of its proper divisors (1).

9943721 is an equidigital number, since it uses as much as digits as its factorization.

9943721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13608, while the sum is 35.

The square root of 9943721 is about 3153.3666136369. The cubic root of 9943721 is about 215.0385436576.

The spelling of 9943721 in words is "nine million, nine hundred forty-three thousand, seven hundred twenty-one".