91087391 has 8 divisors (see below), whose sum is σ = 92534400. Its totient is φ = 89645080.

The previous prime is 91087369. The next prime is 91087417. The reversal of 91087391 is 19378019.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 91087391 - 2¹⁸ = 90825247 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 (91087351) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 71720 + ... + 72978.

It is an arithmetic number, because the mean of its divisors is an integer number (11566800).

Almost surely, 2^91087391 is an apocalyptic number.

91087391 is a deficient number, since it is larger than the sum of its proper divisors (1447009).

91087391 is a wasteful number, since it uses less digits than its factorization.

91087391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2349.

The product of its (nonzero) digits is 13608, while the sum is 38.

The square root of 91087391 is about 9543.9714479875. The cubic root of 91087391 is about 449.9380836623.

The spelling of 91087391 in words is "ninety-one million, eighty-seven thousand, three hundred ninety-one".