91993140 has 72 divisors (see below), whose sum is σ = 282908808. Its totient is φ = 24192000.

The previous prime is 91993129. The next prime is 91993141. The reversal of 91993140 is 4139919.

It can be written as a sum of positive squares in 4 ways, for example, as 8928144 + 83064996 = 2988^2 + 9114^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 91993095 and 91993104.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91993141) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 9640 + ... + 16640.

It is an arithmetic number, because the mean of its divisors is an integer number (3929289).

Almost surely, 2^91993140 is an apocalyptic number.

91993140 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 91993140, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (141454404).

91993140 is an abundant number, since it is smaller than the sum of its proper divisors (190915668).

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

91993140 is a wasteful number, since it uses less digits than its factorization.

91993140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7089 (or 7084 counting only the distinct ones).

The product of its (nonzero) digits is 8748, while the sum is 36.

The square root of 91993140 is about 9591.3054377389. The cubic root of 91993140 is about 451.4245228004.

The spelling of 91993140 in words is "ninety-one million, nine hundred ninety-three thousand, one hundred forty".