91278863475840 has 1536 divisors, whose sum is σ = 343185942528000. Its totient is φ = 22296796397568.

The previous prime is 91278863475739. The next prime is 91278863475841. The reversal of 91278863475840 is 4857436887219.

It is a happy number.

91278863475840 is a `hidden beast` number, since 9 + 1 + 2 + 7 + 8 + 8 + 6 + 34 + 7 + 584 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is not an unprimeable number, because it can be changed into a prime (91278863475841) 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, 82755088729 + ... + 82755089831.

It is an arithmetic number, because the mean of its divisors is an integer number (223428348000).

It is a 1-persistent number, because it is pandigital, but 2⋅91278863475840 = 182557726951680 is not.

Almost surely, 2^{91278863475840} is an apocalyptic number.

91278863475840 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 91278863475840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (171592971264000).

91278863475840 is an abundant number, since it is smaller than the sum of its proper divisors (251907079052160).

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

91278863475840 is a wasteful number, since it uses less digits than its factorization.

91278863475840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1466 (or 1451 counting only the distinct ones).

The product of its (nonzero) digits is 650280960, while the sum is 72.

The spelling of 91278863475840 in words is "ninety-one trillion, two hundred seventy-eight billion, eight hundred sixty-three million, four hundred seventy-five thousand, eight hundred forty".