9994409921 has 2 divisors, whose sum is σ = 9994409922. Its totient is φ = 9994409920.

The previous prime is 9994409801. The next prime is 9994409923. The reversal of 9994409921 is 1299044999.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 9976014400 + 18395521 = 99880^2 + 4289^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-9994409921 is a prime.

Together with 9994409923, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (9994409923) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4997204960 + 4997204961.

It is an arithmetic number, because the mean of its divisors is an integer number (4997204961).

Almost surely, 2^9994409921 is an apocalyptic number.

It is an amenable number.

9994409921 is a deficient number, since it is larger than the sum of its proper divisors (1).

9994409921 is an equidigital number, since it uses as much as digits as its factorization.

9994409921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1889568, while the sum is 56.

The square root of 9994409921 is about 99972.0456977849. The cubic root of 9994409921 is about 2154.0331665337.

The spelling of 9994409921 in words is "nine billion, nine hundred ninety-four million, four hundred nine thousand, nine hundred twenty-one".