91320840 has 288 divisors, whose sum is σ = 342576000. Its totient is φ = 21026304.

The previous prime is 91320829. The next prime is 91320851. The reversal of 91320840 is 4802319.

It is an interprime number because it is at equal distance from previous prime (91320829) and next prime (91320851).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 1155921 + ... + 1155999.

It is an arithmetic number, because the mean of its divisors is an integer number (1189500).

Almost surely, 2^91320840 is an apocalyptic number.

91320840 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 91320840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (171288000).

91320840 is an abundant number, since it is smaller than the sum of its proper divisors (251255160).

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

91320840 is a wasteful number, since it uses less digits than its factorization.

91320840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 141 (or 121 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 91320840 is about 9556.1938029741. The cubic root of 91320840 is about 450.3221397065.

The spelling of 91320840 in words is "ninety-one million, three hundred twenty thousand, eight hundred forty".