91001091901 has 4 divisors (see below), whose sum is σ = 91363646304. Its totient is φ = 90638537500.

The previous prime is 91001091893. The next prime is 91001091911. The reversal of 91001091901 is 10919010019.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 10919010019 = 17 ⋅642294707.

It is a cyclic number.

It is not a de Polignac number, because 91001091901 - 2³ = 91001091893 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91001091911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 181276825 + ... + 181277326.

It is an arithmetic number, because the mean of its divisors is an integer number (22840911576).

Almost surely, 2^91001091901 is an apocalyptic number.

It is an amenable number.

91001091901 is a deficient number, since it is larger than the sum of its proper divisors (362554403).

91001091901 is a wasteful number, since it uses less digits than its factorization.

91001091901 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 362554402.

The product of its (nonzero) digits is 729, while the sum is 31.

The spelling of 91001091901 in words is "ninety-one billion, one million, ninety-one thousand, nine hundred one".