91981327680 has 896 divisors, whose sum is σ = 382380134400. Its totient is φ = 20579328000.

The previous prime is 91981327667. The next prime is 91981327687. The reversal of 91981327680 is 8672318919.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91981327687) 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, 63390955 + ... + 63392405.

Almost surely, 2^91981327680 is an apocalyptic number.

91981327680 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 91981327680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (191190067200).

91981327680 is an abundant number, since it is smaller than the sum of its proper divisors (290398806720).

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

91981327680 is a wasteful number, since it uses less digits than its factorization.

91981327680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1540 (or 1524 counting only the distinct ones).

The product of its (nonzero) digits is 1306368, while the sum is 54.

The spelling of 91981327680 in words is "ninety-one billion, nine hundred eighty-one million, three hundred twenty-seven thousand, six hundred eighty".