91819609 has 16 divisors (see below), whose sum is σ = 111715200. Its totient is φ = 73713024.

The previous prime is 91819549. The next prime is 91819631. The reversal of 91819609 is 90691819.

It is not a de Polignac number, because 91819609 - 2⁹ = 91819097 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91819639) 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, 7959 + ... + 15715.

It is an arithmetic number, because the mean of its divisors is an integer number (6982200).

Almost surely, 2^91819609 is an apocalyptic number.

It is an amenable number.

91819609 is a deficient number, since it is larger than the sum of its proper divisors (19895591).

91819609 is a wasteful number, since it uses less digits than its factorization.

91819609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7872.

The product of its (nonzero) digits is 34992, while the sum is 43.

The square root of 91819609 is about 9582.2549016398. The cubic root of 91819609 is about 451.1404963431.

The spelling of 91819609 in words is "ninety-one million, eight hundred nineteen thousand, six hundred nine".