91291440 has 80 divisors (see below), whose sum is σ = 288383328. Its totient is φ = 23881728.

The previous prime is 91291427. The next prime is 91291463. The reversal of 91291440 is 4419219.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 91291398 and 91291407.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9132 + ... + 16308.

Almost surely, 2^91291440 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 91291440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (144191664).

91291440 is an abundant number, since it is smaller than the sum of its proper divisors (197091888).

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

91291440 is a wasteful number, since it uses less digits than its factorization.

91291440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7246 (or 7240 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 30.

The square root of 91291440 is about 9554.6554097989. The cubic root of 91291440 is about 450.2738086722.

The spelling of 91291440 in words is "ninety-one million, two hundred ninety-one thousand, four hundred forty".