91669 has 6 divisors (see below), whose sum is σ = 95810. Its totient is φ = 87696.

The previous prime is 91639. The next prime is 91673. The reversal of 91669 is 96619.

It can be written as a sum of positive squares in 3 ways, for example, as 22500 + 69169 = 150^2 + 263^2 .

It is not a de Polignac number, because 91669 - 2⁷ = 91541 is a prime.

It is a super-2 number, since 2×91669² = 16806411122, which contains 22 as substring.

It is a Duffinian number.

It is a plaindrome in base 14.

It is a self number, because there is not a number n which added to its sum of digits gives 91669.

It is a congruent number.

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 5 ways as a sum of consecutive naturals, for example, 787 + ... + 895.

2⁹¹⁶⁶⁹ is an apocalyptic number.

It is an amenable number.

91669 is a deficient number, since it is larger than the sum of its proper divisors (4141).

91669 is a wasteful number, since it uses less digits than its factorization.

91669 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 167 (or 138 counting only the distinct ones).

The product of its digits is 2916, while the sum is 31.

The square root of 91669 is about 302.7688887584. The cubic root of 91669 is about 45.0893697199.

Subtracting 91669 from its reverse (96619), we obtain a triangular number (4950 = T₉₉).

The spelling of 91669 in words is "ninety-one thousand, six hundred sixty-nine".