91780128 has 288 divisors, whose sum is σ = 313709760. Its totient is φ = 26127360.

The previous prime is 91780121. The next prime is 91780163. The reversal of 91780128 is 82108719.

It is a tau number, because it is divible by the number of its divisors (288).

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 = 91780092 and 91780101.

It is not an unprimeable number, because it can be changed into a prime (91780121) by changing a digit.

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 47 ways as a sum of consecutive naturals, for example, 2480526 + ... + 2480562.

It is an arithmetic number, because the mean of its divisors is an integer number (1089270).

Almost surely, 2^91780128 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 91780128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (156854880).

91780128 is an abundant number, since it is smaller than the sum of its proper divisors (221929632).

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

91780128 is a wasteful number, since it uses less digits than its factorization.

91780128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 102 (or 82 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 36.

The square root of 91780128 is about 9580.1945700492. The cubic root of 91780128 is about 451.0758259471.

The spelling of 91780128 in words is "ninety-one million, seven hundred eighty thousand, one hundred twenty-eight".