91973728 has 96 divisors (see below), whose sum is σ = 228130560. Its totient is φ = 35458560.

The previous prime is 91973663. The next prime is 91973753. The reversal of 91973728 is 82737919.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 401518 + ... + 401746.

It is an arithmetic number, because the mean of its divisors is an integer number (2376360).

Almost surely, 2^91973728 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 91973728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (114065280).

91973728 is an abundant number, since it is smaller than the sum of its proper divisors (136156832).

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

91973728 is a wasteful number, since it uses less digits than its factorization.

91973728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 420 (or 412 counting only the distinct ones).

The product of its digits is 190512, while the sum is 46.

The square root of 91973728 is about 9590.2934261679. The cubic root of 91973728 is about 451.3927680076.

It can be divided in two parts, 919 and 73728, that added together give a palindrome (74647).

The spelling of 91973728 in words is "ninety-one million, nine hundred seventy-three thousand, seven hundred twenty-eight".