991294891 has 2 divisors, whose sum is σ = 991294892. Its totient is φ = 991294890.

The previous prime is 991294883. The next prime is 991294903. The reversal of 991294891 is 198492199.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 991294891 - 2³ = 991294883 is a prime.

It is not a weakly prime, because it can be changed into another prime (991294991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495647445 + 495647446.

It is an arithmetic number, because the mean of its divisors is an integer number (495647446).

Almost surely, 2^991294891 is an apocalyptic number.

991294891 is a deficient number, since it is larger than the sum of its proper divisors (1).

991294891 is an equidigital number, since it uses as much as digits as its factorization.

991294891 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 419904, while the sum is 52.

The square root of 991294891 is about 31484.8358896787. The cubic root of 991294891 is about 997.0898361619.

The spelling of 991294891 in words is "nine hundred ninety-one million, two hundred ninety-four thousand, eight hundred ninety-one".