91351890 has 96 divisors (see below), whose sum is σ = 278853120. Its totient is φ = 20310912.

The previous prime is 91351877. The next prime is 91351901. The reversal of 91351890 is 9815319.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 21351 + ... + 25269.

It is an arithmetic number, because the mean of its divisors is an integer number (2904720).

Almost surely, 2^91351890 is an apocalyptic number.

91351890 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 91351890, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (139426560).

91351890 is an abundant number, since it is smaller than the sum of its proper divisors (187501230).

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

91351890 is a wasteful number, since it uses less digits than its factorization.

91351890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3976 (or 3973 counting only the distinct ones).

The product of its (nonzero) digits is 9720, while the sum is 36.

The square root of 91351890 is about 9557.8182656922. The cubic root of 91351890 is about 450.3731719353.

It can be divided in two parts, 9135 and 1890, that added together give a square (11025 = 105²).

The spelling of 91351890 in words is "ninety-one million, three hundred fifty-one thousand, eight hundred ninety".