191091216 has 20 divisors (see below), whose sum is σ = 493652432. Its totient is φ = 63697056.

The previous prime is 191091191. The next prime is 191091217. The reversal of 191091216 is 612190191.

It is not an unprimeable number, because it can be changed into a prime (191091217) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1990486 + ... + 1990581.

Almost surely, 2^191091216 is an apocalyptic number.

191091216 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

191091216 is an abundant number, since it is smaller than the sum of its proper divisors (302561216).

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

191091216 is a wasteful number, since it uses less digits than its factorization.

191091216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3981078 (or 3981072 counting only the distinct ones).

The product of its (nonzero) digits is 972, while the sum is 30.

The square root of 191091216 is about 13823.5746462339. The cubic root of 191091216 is about 575.9881845570.

The spelling of 191091216 in words is "one hundred ninety-one million, ninety-one thousand, two hundred sixteen".