91801144440 has 384 divisors, whose sum is σ = 327673382400. Its totient is φ = 22189178880.

The previous prime is 91801144411. The next prime is 91801144511. The reversal of 91801144440 is 4444110819.

91801144440 is a `hidden beast` number, since 91 + 80 + 11 + 44 + 440 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 91801144395 and 91801144404.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 43444824 + ... + 43446936.

It is an arithmetic number, because the mean of its divisors is an integer number (853316100).

Almost surely, 2^91801144440 is an apocalyptic number.

91801144440 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 91801144440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (163836691200).

91801144440 is an abundant number, since it is smaller than the sum of its proper divisors (235872237960).

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

91801144440 is a wasteful number, since it uses less digits than its factorization.

91801144440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2407 (or 2400 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 36.

The spelling of 91801144440 in words is "ninety-one billion, eight hundred one million, one hundred forty-four thousand, four hundred forty".