1991740907520 has 1568 divisors, whose sum is σ = 8832404008512. Its totient is φ = 419662135296.

The previous prime is 1991740907419. The next prime is 1991740907539. The reversal of 1991740907520 is 257090471991.

1991740907520 is a `hidden beast` number, since 19 + 9 + 17 + 4 + 0 + 90 + 7 + 520 = 666.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 111 ways as a sum of consecutive naturals, for example, 2717245074 + ... + 2717245806.

Almost surely, 2^{1991740907520} is an apocalyptic number.

1991740907520 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 1991740907520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4416202004256).

1991740907520 is an abundant number, since it is smaller than the sum of its proper divisors (6840663100992).

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

1991740907520 is an frugal number, since it uses more digits than its factorization.

1991740907520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 802 (or 763 counting only the distinct ones).

The product of its (nonzero) digits is 1428840, while the sum is 54.

The spelling of 1991740907520 in words is "one trillion, nine hundred ninety-one billion, seven hundred forty million, nine hundred seven thousand, five hundred twenty".