91433251728 has 240 divisors, whose sum is σ = 317422350336. Its totient is φ = 23923952640.

The previous prime is 91433251727. The next prime is 91433251739. The reversal of 91433251728 is 82715233419.

It is a happy number.

91433251728 is a `hidden beast` number, since 91 + 43 + 3 + 2 + 517 + 2 + 8 = 666.

It is not an unprimeable number, because it can be changed into a prime (91433251727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1636738 + ... + 1691678.

Almost surely, 2^91433251728 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 91433251728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (158711175168).

91433251728 is an abundant number, since it is smaller than the sum of its proper divisors (225989098608).

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

91433251728 is a wasteful number, since it uses less digits than its factorization.

91433251728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55102 (or 55093 counting only the distinct ones).

The product of its digits is 362880, while the sum is 45.

The spelling of 91433251728 in words is "ninety-one billion, four hundred thirty-three million, two hundred fifty-one thousand, seven hundred twenty-eight".