1991625988716 has 576 divisors, whose sum is σ = 6883192995840. Its totient is φ = 486196888320.

The previous prime is 1991625988643. The next prime is 1991625988717. The reversal of 1991625988716 is 6178895261991.

1991625988716 is a `hidden beast` number, since 1 + 9 + 9 + 16 + 2 + 598 + 8 + 7 + 16 = 666.

It is not an unprimeable number, because it can be changed into a prime (1991625988717) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 91084801 + ... + 91106663.

It is an arithmetic number, because the mean of its divisors is an integer number (11949987840).

Almost surely, 2^{1991625988716} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1991625988716, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3441596497920).

1991625988716 is an abundant number, since it is smaller than the sum of its proper divisors (4891567007124).

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

1991625988716 is a wasteful number, since it uses less digits than its factorization.

1991625988716 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21963 (or 21942 counting only the distinct ones).

The product of its digits is 117573120, while the sum is 72.

The spelling of 1991625988716 in words is "one trillion, nine hundred ninety-one billion, six hundred twenty-five million, nine hundred eighty-eight thousand, seven hundred sixteen".