991325789999 has 16 divisors (see below), whose sum is σ = 1052440883520. Its totient is φ = 932310812160.

The previous prime is 991325789957. The next prime is 991325790031. The reversal of 991325789999 is 999987523199.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 991325789999 - 2⁸ = 991325789743 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991325789099) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2538122 + ... + 2902535.

It is an arithmetic number, because the mean of its divisors is an integer number (65777555220).

Almost surely, 2^991325789999 is an apocalyptic number.

991325789999 is a deficient number, since it is larger than the sum of its proper divisors (61115093521).

991325789999 is a wasteful number, since it uses less digits than its factorization.

991325789999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5440850.

The product of its digits is 892820880, while the sum is 80.

The spelling of 991325789999 in words is "nine hundred ninety-one billion, three hundred twenty-five million, seven hundred eighty-nine thousand, nine hundred ninety-nine".