991900909912 has 32 divisors (see below), whose sum is σ = 2135671819200. Its totient is φ = 427134362400.

The previous prime is 991900909897. The next prime is 991900909919. The reversal of 991900909912 is 219909009199.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991900909919) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 296619414 + ... + 296622757.

It is an arithmetic number, because the mean of its divisors is an integer number (66739744350).

Almost surely, 2^991900909912 is an apocalyptic number.

It is an amenable number.

991900909912 is an abundant number, since it is smaller than the sum of its proper divisors (1143770909288).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

991900909912 is a wasteful number, since it uses less digits than its factorization.

991900909912 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 593242207 (or 593242203 counting only the distinct ones).

The product of its (nonzero) digits is 1062882, while the sum is 58.

The spelling of 991900909912 in words is "nine hundred ninety-one billion, nine hundred million, nine hundred nine thousand, nine hundred twelve".