91136515909 has 4 divisors (see below), whose sum is σ = 91138936140. Its totient is φ = 91134095680.

The previous prime is 91136515871. The next prime is 91136515957. The reversal of 91136515909 is 90951563119.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 86835123684 + 4301392225 = 294678^2 + 65585^2 .

It is a cyclic number.

It is not a de Polignac number, because 91136515909 - 2⁷ = 91136515781 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 (91136515409) 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, 1152724 + ... + 1229245.

It is an arithmetic number, because the mean of its divisors is an integer number (22784734035).

Almost surely, 2^91136515909 is an apocalyptic number.

It is an amenable number.

91136515909 is a deficient number, since it is larger than the sum of its proper divisors (2420231).

91136515909 is a wasteful number, since it uses less digits than its factorization.

91136515909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2420230.

The product of its (nonzero) digits is 328050, while the sum is 49.

The spelling of 91136515909 in words is "ninety-one billion, one hundred thirty-six million, five hundred fifteen thousand, nine hundred nine".