91085379840 has 1728 divisors, whose sum is σ = 433910131200. Its totient is φ = 17071865856.

The previous prime is 91085379799. The next prime is 91085379863. The reversal of 91085379840 is 4897358019.

91085379840 is a `hidden beast` number, since 9 + 10 + 8 + 537 + 98 + 4 + 0 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 338607226 + ... + 338607494.

It is an arithmetic number, because the mean of its divisors is an integer number (251105400).

Almost surely, 2^91085379840 is an apocalyptic number.

91085379840 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 91085379840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (216955065600).

91085379840 is an abundant number, since it is smaller than the sum of its proper divisors (342824751360).

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

91085379840 is a wasteful number, since it uses less digits than its factorization.

91085379840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 352 (or 335 counting only the distinct ones).

The product of its (nonzero) digits is 2177280, while the sum is 54.

The spelling of 91085379840 in words is "ninety-one billion, eighty-five million, three hundred seventy-nine thousand, eight hundred forty".