91991448 has 72 divisors (see below), whose sum is σ = 255441420. Its totient is φ = 29907360.

The previous prime is 91991441. The next prime is 91991453. The reversal of 91991448 is 84419919.

It is a tau number, because it is divible by the number of its divisors (72).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91991441) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 132783 + ... + 133473.

Almost surely, 2^91991448 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 91991448, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (127720710).

91991448 is an abundant number, since it is smaller than the sum of its proper divisors (163449972).

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

91991448 is a wasteful number, since it uses less digits than its factorization.

91991448 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 789 (or 739 counting only the distinct ones).

The product of its digits is 93312, while the sum is 45.

The square root of 91991448 is about 9591.2172324476. The cubic root of 91991448 is about 451.4217551485.

The spelling of 91991448 in words is "ninety-one million, nine hundred ninety-one thousand, four hundred forty-eight".