1991688410250 has 384 divisors, whose sum is σ = 6851479564800. Its totient is φ = 413855568000.

The previous prime is 1991688410227. The next prime is 1991688410251. The reversal of 1991688410250 is 520148861991.

1991688410250 is a `hidden beast` number, since 1 + 99 + 16 + 88 + 410 + 2 + 50 = 666.

It is not an unprimeable number, because it can be changed into a prime (1991688410251) by changing a digit.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 8371944 + ... + 8606556.

It is an arithmetic number, because the mean of its divisors is an integer number (17842394700).

Almost surely, 2^{1991688410250} is an apocalyptic number.

1991688410250 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1991688410250, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3425739782400).

1991688410250 is an abundant number, since it is smaller than the sum of its proper divisors (4859791154550).

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

1991688410250 is a wasteful number, since it uses less digits than its factorization.

1991688410250 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 234668 (or 234641 counting only the distinct ones).

The product of its (nonzero) digits is 1244160, while the sum is 54.

The spelling of 1991688410250 in words is "one trillion, nine hundred ninety-one billion, six hundred eighty-eight million, four hundred ten thousand, two hundred fifty".