9640991 has 2 divisors, whose sum is σ = 9640992. Its totient is φ = 9640990.

The previous prime is 9640973. The next prime is 9640993. The reversal of 9640991 is 1990469.

9640991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 9640991 - 2¹⁸ = 9378847 is a prime.

Together with 9640993, 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 (9640993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4820495 + 4820496.

It is an arithmetic number, because the mean of its divisors is an integer number (4820496).

Almost surely, 2^9640991 is an apocalyptic number.

9640991 is a deficient number, since it is larger than the sum of its proper divisors (1).

9640991 is an equidigital number, since it uses as much as digits as its factorization.

9640991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 17496, while the sum is 38.

The square root of 9640991 is about 3104.9945249549. The cubic root of 9640991 is about 212.8337804058.

The spelling of 9640991 in words is "nine million, six hundred forty thousand, nine hundred ninety-one".