91717920 has 288 divisors, whose sum is σ = 372048768. Its totient is φ = 20901888.

The previous prime is 91717909. The next prime is 91717957. The reversal of 91717920 is 2971719.

It is a tau number, because it is divible by the number of its divisors (288).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 271992 + ... + 272328.

It is an arithmetic number, because the mean of its divisors is an integer number (1291836).

Almost surely, 2^91717920 is an apocalyptic number.

91717920 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 91717920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (186024384).

91717920 is an abundant number, since it is smaller than the sum of its proper divisors (280330848).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

91717920 is a wasteful number, since it uses less digits than its factorization.

91717920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 374 (or 354 counting only the distinct ones).

The product of its (nonzero) digits is 7938, while the sum is 36.

The square root of 91717920 is about 9576.9473215634. The cubic root of 91717920 is about 450.9738907834.

The spelling of 91717920 in words is "ninety-one million, seven hundred seventeen thousand, nine hundred twenty".