991329212400 has 60 divisors (see below), whose sum is σ = 3175557914232. Its totient is φ = 264354456320.

The previous prime is 991329212399. The next prime is 991329212413. The reversal of 991329212400 is 4212923199.

It is a tau number, because it is divible by the number of its divisors (60).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 413052639 + ... + 413055038.

Almost surely, 2^991329212400 is an apocalyptic number.

It is an amenable number.

991329212400 is an abundant number, since it is smaller than the sum of its proper divisors (2184228701832).

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

991329212400 is a wasteful number, since it uses less digits than its factorization.

991329212400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 826107698 (or 826107687 counting only the distinct ones).

The product of its (nonzero) digits is 69984, while the sum is 42.

The spelling of 991329212400 in words is "nine hundred ninety-one billion, three hundred twenty-nine million, two hundred twelve thousand, four hundred".