91217609 has 16 divisors (see below), whose sum is σ = 109105920. Its totient is φ = 74564160.

The previous prime is 91217603. The next prime is 91217641. The reversal of 91217609 is 90671219.

It is a de Polignac number, because none of the positive numbers 2^k-91217609 is a prime.

It is not an unprimeable number, because it can be changed into a prime (91217603) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 73607 + ... + 74835.

It is an arithmetic number, because the mean of its divisors is an integer number (6819120).

Almost surely, 2^91217609 is an apocalyptic number.

It is an amenable number.

91217609 is a deficient number, since it is larger than the sum of its proper divisors (17888311).

91217609 is a wasteful number, since it uses less digits than its factorization.

91217609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1720.

The product of its (nonzero) digits is 6804, while the sum is 35.

The square root of 91217609 is about 9550.7910143611. The cubic root of 91217609 is about 450.1523911857.

The spelling of 91217609 in words is "ninety-one million, two hundred seventeen thousand, six hundred nine".