91815286855680 has 384 divisors, whose sum is σ = 343552285440000. Its totient is φ = 23195439562752.

The previous prime is 91815286855553. The next prime is 91815286855723. The reversal of 91815286855680 is 8655868251819.

It is a happy number.

91815286855680 is a `hidden beast` number, since 9 + 1 + 8 + 1 + 5 + 2 + 8 + 68 + 556 + 8 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (384).

It is a super-2 number, since 2×91815286855680² (a number of 29 digits) contains 22 as substring.

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

It is a junction number, because it is equal to n+sod(n) for n = 91815286855599 and 91815286855608.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3486000 + ... + 13992239.

It is an arithmetic number, because the mean of its divisors is an integer number (894667410000).

Almost surely, 2^{91815286855680} is an apocalyptic number.

91815286855680 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 91815286855680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (171776142720000).

91815286855680 is an abundant number, since it is smaller than the sum of its proper divisors (251736998584320).

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

91815286855680 is a wasteful number, since it uses less digits than its factorization.

91815286855680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17478294 (or 17478268 counting only the distinct ones).

The product of its (nonzero) digits is 331776000, while the sum is 72.

The spelling of 91815286855680 in words is "ninety-one trillion, eight hundred fifteen billion, two hundred eighty-six million, eight hundred fifty-five thousand, six hundred eighty".