91081998 has 48 divisors (see below), whose sum is σ = 230795136. Its totient is φ = 25416720.

The previous prime is 91081997. The next prime is 91082003. The reversal of 91081998 is 89918019.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91081993) 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, 2988 + ... + 13823.

It is an arithmetic number, because the mean of its divisors is an integer number (4808232).

Almost surely, 2^91081998 is an apocalyptic number.

91081998 is an abundant number, since it is smaller than the sum of its proper divisors (139713138).

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

91081998 is a wasteful number, since it uses less digits than its factorization.

91081998 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16869 (or 16866 counting only the distinct ones).

The product of its (nonzero) digits is 46656, while the sum is 45.

The square root of 91081998 is about 9543.6889094312. The cubic root of 91081998 is about 449.9292036774.

The spelling of 91081998 in words is "ninety-one million, eighty-one thousand, nine hundred ninety-eight".