91997995140 has 288 divisors, whose sum is σ = 299345155200. Its totient is φ = 22826280960.

The previous prime is 91997995121. The next prime is 91997995151. The reversal of 91997995140 is 4159979919.

It is a super-2 number, since 2×91997995140² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 17761071 + ... + 17766249.

It is an arithmetic number, because the mean of its divisors is an integer number (1039392900).

Almost surely, 2^91997995140 is an apocalyptic number.

91997995140 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 91997995140, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (149672577600).

91997995140 is an abundant number, since it is smaller than the sum of its proper divisors (207347160060).

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

91997995140 is a wasteful number, since it uses less digits than its factorization.

91997995140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5347 (or 5342 counting only the distinct ones).

The product of its (nonzero) digits is 8266860, while the sum is 63.

The spelling of 91997995140 in words is "ninety-one billion, nine hundred ninety-seven million, nine hundred ninety-five thousand, one hundred forty".