91718609 has 4 divisors (see below), whose sum is σ = 91751220. Its totient is φ = 91686000.

The previous prime is 91718603. The next prime is 91718611. The reversal of 91718609 is 90681719.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 25654225 + 66064384 = 5065^2 + 8128^2 .

It is a cyclic number.

It is not a de Polignac number, because 91718609 - 2⁴ = 91718593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91718603) 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, 11642 + ... + 17859.

It is an arithmetic number, because the mean of its divisors is an integer number (22937805).

Almost surely, 2^91718609 is an apocalyptic number.

It is an amenable number.

91718609 is a deficient number, since it is larger than the sum of its proper divisors (32611).

91718609 is a wasteful number, since it uses less digits than its factorization.

91718609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32610.

The product of its (nonzero) digits is 27216, while the sum is 41.

The square root of 91718609 is about 9576.9832932923. The cubic root of 91718609 is about 450.9750200437.

The spelling of 91718609 in words is "ninety-one million, seven hundred eighteen thousand, six hundred nine".