91090706805840 has 640 divisors, whose sum is σ = 331802427285504. Its totient is φ = 20238704640000.

The previous prime is 91090706805823. The next prime is 91090706805841. The reversal of 91090706805840 is 4850860709019.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91090706805841) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 35990005375 + ... + 35990007905.

Almost surely, 2^{91090706805840} 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 91090706805840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (165901213642752).

91090706805840 is an abundant number, since it is smaller than the sum of its proper divisors (240711720479664).

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

91090706805840 is a wasteful number, since it uses less digits than its factorization.

91090706805840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4299 (or 4293 counting only the distinct ones).

The product of its (nonzero) digits is 4354560, while the sum is 57.

The spelling of 91090706805840 in words is "ninety-one trillion, ninety billion, seven hundred six million, eight hundred five thousand, eight hundred forty".