91217664 has 180 divisors, whose sum is σ = 280465416. Its totient is φ = 29472768.

The previous prime is 91217653. The next prime is 91217669. The reversal of 91217664 is 46671219.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91217669) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1098967 + ... + 1099049.

Almost surely, 2^91217664 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 91217664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (140232708).

91217664 is an abundant number, since it is smaller than the sum of its proper divisors (189247752).

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

91217664 is an equidigital number, since it uses as much as digits as its factorization.

91217664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 164 (or 141 counting only the distinct ones).

The product of its digits is 18144, while the sum is 36.

The square root of 91217664 is about 9550.7938937033. The cubic root of 91217664 is about 450.1524816594.

The spelling of 91217664 in words is "ninety-one million, two hundred seventeen thousand, six hundred sixty-four".