1991698450560 has 2048 divisors, whose sum is σ = 9262761984000. Its totient is φ = 397625573376.

The previous prime is 1991698450523. The next prime is 1991698450603. The reversal of 1991698450560 is 650548961991.

1991698450560 is a `hidden beast` number, since 1 + 9 + 9 + 1 + 69 + 8 + 4 + 5 + 0 + 560 = 666.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is an unprimeable number.

It is a polite number, since it can be written in 255 ways as a sum of consecutive naturals, for example, 2420046309 + ... + 2420047131.

It is an arithmetic number, because the mean of its divisors is an integer number (4522833000).

Almost surely, 2^{1991698450560} is an apocalyptic number.

1991698450560 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 1991698450560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4631380992000).

1991698450560 is an abundant number, since it is smaller than the sum of its proper divisors (7271063533440).

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

1991698450560 is an equidigital number, since it uses as much as digits as its factorization.

1991698450560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 902 (or 872 counting only the distinct ones).

The product of its (nonzero) digits is 20995200, while the sum is 63.

The spelling of 1991698450560 in words is "one trillion, nine hundred ninety-one billion, six hundred ninety-eight million, four hundred fifty thousand, five hundred sixty".