91290240 has 192 divisors, whose sum is σ = 327468960. Its totient is φ = 24302592.

The previous prime is 91290217. The next prime is 91290253. The reversal of 91290240 is 4209219.

It is a tau number, because it is divible by the number of its divisors (192).

It is a Harshad number since it is a multiple of its sum of digits (27).

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, 155227 + ... + 155813.

Almost surely, 2^91290240 is an apocalyptic number.

91290240 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 91290240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (163734480).

91290240 is an abundant number, since it is smaller than the sum of its proper divisors (236178720).

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

91290240 is an equidigital number, since it uses as much as digits as its factorization.

91290240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 621 (or 597 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 91290240 is about 9554.5926129794. The cubic root of 91290240 is about 450.2718357565.

Adding to 91290240 its reverse (4209219), we get a palindrome (95499459).

The spelling of 91290240 in words is "ninety-one million, two hundred ninety thousand, two hundred forty".