91377447840 has 1152 divisors, whose sum is σ = 399435079680. Its totient is φ = 19259596800.

The previous prime is 91377447839. The next prime is 91377447841. The reversal of 91377447840 is 4874477319.

91377447840 is a `hidden beast` number, since 91 + 3 + 77 + 447 + 8 + 40 = 666.

It is an interprime number because it is at equal distance from previous prime (91377447839) and next prime (91377447841).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (91377447841) by changing a digit.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 212012425 + ... + 212012855.

It is an arithmetic number, because the mean of its divisors is an integer number (346731840).

Almost surely, 2^91377447840 is an apocalyptic number.

91377447840 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 91377447840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (199717539840).

91377447840 is an abundant number, since it is smaller than the sum of its proper divisors (308057631840).

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

91377447840 is a wasteful number, since it uses less digits than its factorization.

91377447840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 528 (or 508 counting only the distinct ones).

The product of its (nonzero) digits is 4741632, while the sum is 54.

The spelling of 91377447840 in words is "ninety-one billion, three hundred seventy-seven million, four hundred forty-seven thousand, eight hundred forty".