191981808 has 60 divisors (see below), whose sum is σ = 538698160. Its totient is φ = 63825408.

The previous prime is 191981807. The next prime is 191981831. The reversal of 191981808 is 808189191.

191981808 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (191981807) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 60813 + ... + 63891.

Almost surely, 2^191981808 is an apocalyptic number.

191981808 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

191981808 is an abundant number, since it is smaller than the sum of its proper divisors (346716352).

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

191981808 is a wasteful number, since it uses less digits than its factorization.

191981808 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3526 (or 3517 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 45.

The square root of 191981808 is about 13855.7499977446. The cubic root of 191981808 is about 576.8816071279.

The spelling of 191981808 in words is "one hundred ninety-one million, nine hundred eighty-one thousand, eight hundred eight".