91000000001 has 16 divisors (see below), whose sum is σ = 95004940800. Its totient is φ = 87067180800.

The previous prime is 90999999973. The next prime is 91000000037. The reversal of 91000000001 is 10000000019.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91000000001 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91000006001) 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 15 ways as a sum of consecutive naturals, for example, 994655 + ... + 1082283.

It is an arithmetic number, because the mean of its divisors is an integer number (5937808800).

Almost surely, 2^91000000001 is an apocalyptic number.

It is an amenable number.

91000000001 is a deficient number, since it is larger than the sum of its proper divisors (4004940799).

91000000001 is a wasteful number, since it uses less digits than its factorization.

91000000001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 88040.

The product of its (nonzero) digits is 9, while the sum is 11.

It can be divided in two parts, 9 and 1000000001, that multiplied together give a palindrome (9000000009).

The spelling of 91000000001 in words is "ninety-one billion, one", and thus it is an aban number and an uban number.