91609 has 8 divisors (see below), whose sum is σ = 109440. Its totient is φ = 74976.

The previous prime is 91591. The next prime is 91621. The reversal of 91609 is 90619.

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 91609 - 2⁵ = 91577 is a prime.

It is a Duffinian number.

It is a plaindrome in base 14.

It is not an unprimeable number, because it can be changed into a prime (91639) 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, 124 + ... + 445.

It is an arithmetic number, because the mean of its divisors is an integer number (13680).

2⁹¹⁶⁰⁹ is an apocalyptic number.

It is an amenable number.

91609 is a deficient number, since it is larger than the sum of its proper divisors (17831).

91609 is a wasteful number, since it uses less digits than its factorization.

91609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 599.

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

The square root of 91609 is about 302.6697870617. The cubic root of 91609 is about 45.0795301426.

Subtracting from 91609 its reverse (90619), we obtain a triangular number (990 = T₄₄).

The spelling of 91609 in words is "ninety-one thousand, six hundred nine".