91001820091 has 8 divisors (see below), whose sum is σ = 112002240224. Its totient is φ = 72001440000.

The previous prime is 91001820083. The next prime is 91001820103. The reversal of 91001820091 is 19002810019.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 91001820091 - 2³ = 91001820083 is a prime.

It is not an unprimeable number, because it can be changed into a prime (91001820001) 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 7 ways as a sum of consecutive naturals, for example, 500009910 + ... + 500010091.

It is an arithmetic number, because the mean of its divisors is an integer number (14000280028).

Almost surely, 2^91001820091 is an apocalyptic number.

91001820091 is a gapful number since it is divisible by the number (91) formed by its first and last digit.

91001820091 is a deficient number, since it is larger than the sum of its proper divisors (21000420133).

91001820091 is a wasteful number, since it uses less digits than its factorization.

91001820091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1000020021.

The product of its (nonzero) digits is 1296, while the sum is 31.

The spelling of 91001820091 in words is "ninety-one billion, one million, eight hundred twenty thousand, ninety-one".