90691 has 4 divisors (see below), whose sum is σ = 91800. Its totient is φ = 89584.

The previous prime is 90679. The next prime is 90697. The reversal of 90691 is 19609.

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

It is a cyclic number.

It is not a de Polignac number, because 90691 - 2⁵ = 90659 is a prime.

It is a Duffinian number.

90691 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (90697) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 421 + ... + 598.

It is an arithmetic number, because the mean of its divisors is an integer number (22950).

2⁹⁰⁶⁹¹ is an apocalyptic number.

90691 is a deficient number, since it is larger than the sum of its proper divisors (1109).

90691 is a wasteful number, since it uses less digits than its factorization.

90691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1108.

The product of its (nonzero) digits is 486, while the sum is 25.

The square root of 90691 is about 301.1494645521. The cubic root of 90691 is about 44.9284459537.

The spelling of 90691 in words is "ninety thousand, six hundred ninety-one".