91291648 has 68 divisors (see below), whose sum is σ = 209713600. Its totient is φ = 38928384.

The previous prime is 91291643. The next prime is 91291657. The reversal of 91291648 is 84619219.

It is a self number, because there is not a number n which added to its sum of digits gives 91291648.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91291643) 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, 458653 + ... + 458851.

Almost surely, 2^91291648 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 91291648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (104856800).

91291648 is an abundant number, since it is smaller than the sum of its proper divisors (118421952).

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

91291648 is an frugal number, since it uses more digits than its factorization.

91291648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 238 (or 208 counting only the distinct ones).

The product of its digits is 31104, while the sum is 40.

The square root of 91291648 is about 9554.6662945390. Note that the first 3 decimals coincide. The cubic root of 91291648 is about 450.2741506425.

The spelling of 91291648 in words is "ninety-one million, two hundred ninety-one thousand, six hundred forty-eight".