91690087 has 4 divisors (see below), whose sum is σ = 91709280. Its totient is φ = 91670896.

The previous prime is 91690073. The next prime is 91690097. The reversal of 91690087 is 78009619.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78009619 = 4337 ⋅17987.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91690087 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91690057) 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, 3858 + ... + 14080.

It is an arithmetic number, because the mean of its divisors is an integer number (22927320).

Almost surely, 2^91690087 is an apocalyptic number.

91690087 is a deficient number, since it is larger than the sum of its proper divisors (19193).

91690087 is a wasteful number, since it uses less digits than its factorization.

91690087 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19192.

The product of its (nonzero) digits is 27216, while the sum is 40.

The square root of 91690087 is about 9575.4940864689. The cubic root of 91690087 is about 450.9282681969.

The spelling of 91690087 in words is "ninety-one million, six hundred ninety thousand, eighty-seven".