1991874931200 has 4320 divisors, whose sum is σ = 10122211154880. Its totient is φ = 379020902400.

The previous prime is 1991874931199. The next prime is 1991874931259. The reversal of 1991874931200 is 21394781991.

1991874931200 is a `hidden beast` number, since 19 + 9 + 18 + 7 + 493 + 120 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (4320).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 431 ways as a sum of consecutive naturals, for example, 53834457582 + ... + 53834457618.

It is an arithmetic number, because the mean of its divisors is an integer number (2343104434).

Almost surely, 2^{1991874931200} is an apocalyptic number.

1991874931200 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1991874931200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (5061105577440).

1991874931200 is an abundant number, since it is smaller than the sum of its proper divisors (8130336223680).

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

1991874931200 is a wasteful number, since it uses less digits than its factorization.

1991874931200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133 (or 82 counting only the distinct ones).

The product of its (nonzero) digits is 979776, while the sum is 54.

The spelling of 1991874931200 in words is "one trillion, nine hundred ninety-one billion, eight hundred seventy-four million, nine hundred thirty-one thousand, two hundred".