91861812 has 144 divisors (see below), whose sum is σ = 288392832. Its totient is φ = 24053760.

The previous prime is 91861811. The next prime is 91861843. The reversal of 91861812 is 21816819.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91861811) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 175383 + ... + 175905.

It is an arithmetic number, because the mean of its divisors is an integer number (2002728).

Almost surely, 2^91861812 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 91861812, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (144196416).

91861812 is an abundant number, since it is smaller than the sum of its proper divisors (196531020).

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

91861812 is a wasteful number, since it uses less digits than its factorization.

91861812 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 598 (or 593 counting only the distinct ones).

The product of its digits is 6912, while the sum is 36.

The square root of 91861812 is about 9584.4567921192. The cubic root of 91861812 is about 451.2096049147.

The spelling of 91861812 in words is "ninety-one million, eight hundred sixty-one thousand, eight hundred twelve".