991199966633 has 2 divisors, whose sum is σ = 991199966634. Its totient is φ = 991199966632.

The previous prime is 991199966621. The next prime is 991199966657. The reversal of 991199966633 is 336669991199.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 851270105449 + 139929861184 = 922643^2 + 374072^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-991199966633 is a prime.

It is a zygodrome in base 10.

It is not a weakly prime, because it can be changed into another prime (991199966683) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495599983316 + 495599983317.

It is an arithmetic number, because the mean of its divisors is an integer number (495599983317).

Almost surely, 2^991199966633 is an apocalyptic number.

It is an amenable number.

991199966633 is a deficient number, since it is larger than the sum of its proper divisors (1).

991199966633 is an equidigital number, since it uses as much as digits as its factorization.

991199966633 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 114791256, while the sum is 71.

The spelling of 991199966633 in words is "nine hundred ninety-one billion, one hundred ninety-nine million, nine hundred sixty-six thousand, six hundred thirty-three".