9921599 has 2 divisors, whose sum is σ = 9921600. Its totient is φ = 9921598.

The previous prime is 9921577. The next prime is 9921601. The reversal of 9921599 is 9951299.

It is a strong prime.

It is an emirp because it is prime and its reverse (9951299) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 9921599 - 2⁸ = 9921343 is a prime.

Together with 9921601, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9921529) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4960799 + 4960800.

It is an arithmetic number, because the mean of its divisors is an integer number (4960800).

Almost surely, 2^9921599 is an apocalyptic number.

9921599 is a deficient number, since it is larger than the sum of its proper divisors (1).

9921599 is an equidigital number, since it uses as much as digits as its factorization.

9921599 is an evil number, because the sum of its binary digits is even.

The product of its digits is 65610, while the sum is 44.

The square root of 9921599 is about 3149.8569808802. The cubic root of 9921599 is about 214.8789583691.

The spelling of 9921599 in words is "nine million, nine hundred twenty-one thousand, five hundred ninety-nine".