91000005 has 16 divisors (see below), whose sum is σ = 146025600. Its totient is φ = 48391488.

The previous prime is 90999989. The next prime is 91000009. The reversal of 91000005 is 50000019.

It is not a de Polignac number, because 91000005 - 2⁴ = 90999989 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91000009) 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, 3457 + ... + 13926.

It is an arithmetic number, because the mean of its divisors is an integer number (9126600).

Almost surely, 2^91000005 is an apocalyptic number.

It is an amenable number.

91000005 is a deficient number, since it is larger than the sum of its proper divisors (55025595).

91000005 is a wasteful number, since it uses less digits than its factorization.

91000005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17740.

The product of its (nonzero) digits is 45, while the sum is 15.

The square root of 91000005 is about 9539.3922762407. The cubic root of 91000005 is about 449.7941527655.

The spelling of 91000005 in words is "ninety-one million, five", and thus it is an aban number and an uban number.