9940881791 has 2 divisors, whose sum is σ = 9940881792. Its totient is φ = 9940881790.

The previous prime is 9940881761. The next prime is 9940881793. The reversal of 9940881791 is 1971880499.

9940881791 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 an emirp because it is prime and its reverse (1971880499) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 9940881791 - 2²² = 9936687487 is a prime.

It is a super-2 number, since 2×9940881791² (a number of 21 digits) contains 22 as substring.

Together with 9940881793, 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 (9940881793) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4970440895 + 4970440896.

It is an arithmetic number, because the mean of its divisors is an integer number (4970440896).

Almost surely, 2^9940881791 is an apocalyptic number.

9940881791 is a deficient number, since it is larger than the sum of its proper divisors (1).

9940881791 is an equidigital number, since it uses as much as digits as its factorization.

9940881791 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1306368, while the sum is 56.

The square root of 9940881791 is about 99703.9707885298. The cubic root of 9940881791 is about 2150.1807521373.

The spelling of 9940881791 in words is "nine billion, nine hundred forty million, eight hundred eighty-one thousand, seven hundred ninety-one".