91080091000921 has 27 divisors (see below), whose sum is σ = 101343233347167. Its totient is φ = 81794665626960.

The previous prime is 91080091000907. The next prime is 91080091000967. The reversal of 91080091000921 is 12900019008019.

The square root of 91080091000921 is 9543589.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 89380290433225 + 1699800567696 = 9454115^2 + 1303764^2 .

It is not a de Polignac number, because 91080091000921 - 2⁴¹ = 88881067745369 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91080091000721) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 8713291531 + ... + 8713301983.

Almost surely, 2^{91080091000921} is an apocalyptic number.

91080091000921 is the 9543589-th square number.

91080091000921 is the 4771795-th centered octagonal number.

It is an amenable number.

91080091000921 is a deficient number, since it is larger than the sum of its proper divisors (10263142346246).

91080091000921 is an frugal number, since it uses more digits than its factorization.

91080091000921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21094 (or 10547 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 40.

The spelling of 91080091000921 in words is "ninety-one trillion, eighty billion, ninety-one million, nine hundred twenty-one", and thus it is an aban number.