91718899 has 4 divisors (see below), whose sum is σ = 91869136. Its totient is φ = 91568664.

The previous prime is 91718881. The next prime is 91718903. The reversal of 91718899 is 99881719.

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

It is a cyclic number.

It is not a de Polignac number, because 91718899 - 2⁵ = 91718867 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91718839) 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, 74199 + ... + 75424.

It is an arithmetic number, because the mean of its divisors is an integer number (22967284).

Almost surely, 2^91718899 is an apocalyptic number.

91718899 is a deficient number, since it is larger than the sum of its proper divisors (150237).

91718899 is a wasteful number, since it uses less digits than its factorization.

91718899 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 150236.

The product of its digits is 326592, while the sum is 52.

The square root of 91718899 is about 9576.9984337474. The cubic root of 91718899 is about 450.9754953476.

Subtracting 91718899 from its reverse (99881719), we obtain a triangular number (8162820 = T₄₀₄₀).

The spelling of 91718899 in words is "ninety-one million, seven hundred eighteen thousand, eight hundred ninety-nine".