91000100909 has 4 divisors (see below), whose sum is σ = 91390659516. Its totient is φ = 90609542304.

The previous prime is 91000100903. The next prime is 91000100951. The reversal of 91000100909 is 90900100019.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90900100019 = 17 ⋅5347064707.

It can be written as a sum of positive squares in 2 ways, for example, as 24461898409 + 66538202500 = 156403^2 + 257950^2 .

It is a cyclic number.

It is not a de Polignac number, because 91000100909 - 2¹² = 91000096813 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 (91000100903) 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, 195278954 + ... + 195279419.

It is an arithmetic number, because the mean of its divisors is an integer number (22847664879).

Almost surely, 2^91000100909 is an apocalyptic number.

It is an amenable number.

91000100909 is a deficient number, since it is larger than the sum of its proper divisors (390558607).

91000100909 is a wasteful number, since it uses less digits than its factorization.

91000100909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 390558606.

The product of its (nonzero) digits is 729, while the sum is 29.

The spelling of 91000100909 in words is "ninety-one billion, one hundred thousand, nine hundred nine".