1991693368 has 16 divisors (see below), whose sum is σ = 4267914480. Its totient is φ = 853582848.

The previous prime is 1991693351. The next prime is 1991693369. The reversal of 1991693368 is 8633961991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1991693369) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17782921 + ... + 17783032.

It is an arithmetic number, because the mean of its divisors is an integer number (266744655).

Almost surely, 2^1991693368 is an apocalyptic number.

It is an amenable number.

1991693368 is an abundant number, since it is smaller than the sum of its proper divisors (2276221112).

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

1991693368 is a wasteful number, since it uses less digits than its factorization.

1991693368 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35565966 (or 35565962 counting only the distinct ones).

The product of its digits is 1889568, while the sum is 55.

The square root of 1991693368 is about 44628.3919495202. The cubic root of 1991693368 is about 1258.1743460355.

The spelling of 1991693368 in words is "one billion, nine hundred ninety-one million, six hundred ninety-three thousand, three hundred sixty-eight".