91819091 has 48 divisors (see below), whose sum is σ = 124679520. Its totient is φ = 66769920.

The previous prime is 91819087. The next prime is 91819097. The reversal of 91819091 is 19091819.

It is a happy number.

It is not a de Polignac number, because 91819091 - 2² = 91819087 is a prime.

It is not an unprimeable number, because it can be changed into a prime (91819097) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 660500 + ... + 660638.

It is an arithmetic number, because the mean of its divisors is an integer number (2597490).

Almost surely, 2^91819091 is an apocalyptic number.

91819091 is a gapful number since it is divisible by the number (91) formed by its first and last digit.

91819091 is a deficient number, since it is larger than the sum of its proper divisors (32860429).

91819091 is a wasteful number, since it uses less digits than its factorization.

91819091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 244 (or 237 counting only the distinct ones).

The product of its (nonzero) digits is 5832, while the sum is 38.

The square root of 91819091 is about 9582.2278724731. The cubic root of 91819091 is about 451.1396479723.

The spelling of 91819091 in words is "ninety-one million, eight hundred nineteen thousand, ninety-one".