991294823 has 2 divisors, whose sum is σ = 991294824. Its totient is φ = 991294822.

The previous prime is 991294807. The next prime is 991294877. The reversal of 991294823 is 328492199.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 991294823 - 2⁴ = 991294807 is a prime.

It is a super-3 number, since 3×991294823³ (a number of 28 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (991294883) 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, 495647411 + 495647412.

It is an arithmetic number, because the mean of its divisors is an integer number (495647412).

Almost surely, 2^991294823 is an apocalyptic number.

991294823 is a deficient number, since it is larger than the sum of its proper divisors (1).

991294823 is an equidigital number, since it uses as much as digits as its factorization.

991294823 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 279936, while the sum is 47.

The square root of 991294823 is about 31484.8348097937. The cubic root of 991294823 is about 997.0898133627.

The spelling of 991294823 in words is "nine hundred ninety-one million, two hundred ninety-four thousand, eight hundred twenty-three".