91278411840 has 672 divisors, whose sum is σ = 404540801280. Its totient is φ = 18965422080.

The previous prime is 91278411793. The next prime is 91278411863. The reversal of 91278411840 is 4811487219.

91278411840 is a `hidden beast` number, since 91 + 2 + 78 + 411 + 84 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (672).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

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 95 ways as a sum of consecutive naturals, for example, 7311844 + ... + 7324316.

It is an arithmetic number, because the mean of its divisors is an integer number (601995240).

Almost surely, 2^91278411840 is an apocalyptic number.

91278411840 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 91278411840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (202270400640).

91278411840 is an abundant number, since it is smaller than the sum of its proper divisors (313262389440).

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

91278411840 is a wasteful number, since it uses less digits than its factorization.

91278411840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12528 (or 12501 counting only the distinct ones).

The product of its (nonzero) digits is 129024, while the sum is 45.

The spelling of 91278411840 in words is "ninety-one billion, two hundred seventy-eight million, four hundred eleven thousand, eight hundred forty".