91440720 has 120 divisors (see below), whose sum is σ = 350977536. Its totient is φ = 20899584.

The previous prime is 91440719. The next prime is 91440763. The reversal of 91440720 is 2704419.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (120).

It is a super-2 number, since 2×91440720² = 16722810548236800, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4032 + ... + 14111.

Almost surely, 2^91440720 is an apocalyptic number.

91440720 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 91440720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (175488768).

91440720 is an abundant number, since it is smaller than the sum of its proper divisors (259536816).

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

91440720 is a wasteful number, since it uses less digits than its factorization.

91440720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18169 (or 18160 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 91440720 is about 9562.4641175797. The cubic root of 91440720 is about 450.5191046520.

The spelling of 91440720 in words is "ninety-one million, four hundred forty thousand, seven hundred twenty".