991991760919 has 2 divisors, whose sum is σ = 991991760920. Its totient is φ = 991991760918.

The previous prime is 991991760917. The next prime is 991991760967. The reversal of 991991760919 is 919067199199.

991991760919 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 991991760919 - 2¹ = 991991760917 is a prime.

It is a super-2 number, since 2×991991760919² (a number of 25 digits) contains 22 as substring.

Together with 991991760917, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (991991760917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495995880459 + 495995880460.

It is an arithmetic number, because the mean of its divisors is an integer number (495995880460).

Almost surely, 2^991991760919 is an apocalyptic number.

991991760919 is a deficient number, since it is larger than the sum of its proper divisors (1).

991991760919 is an equidigital number, since it uses as much as digits as its factorization.

991991760919 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 22320522, while the sum is 70.

The spelling of 991991760919 in words is "nine hundred ninety-one billion, nine hundred ninety-one million, seven hundred sixty thousand, nine hundred nineteen".