91097778 has 32 divisors (see below), whose sum is σ = 191642112. Its totient is φ = 28828800.

The previous prime is 91097771. The next prime is 91097789. The reversal of 91097778 is 87779019.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (91097771) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5238 + ... + 14478.

It is an arithmetic number, because the mean of its divisors is an integer number (5988816).

Almost surely, 2^91097778 is an apocalyptic number.

91097778 is an abundant number, since it is smaller than the sum of its proper divisors (100544334).

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

91097778 is a wasteful number, since it uses less digits than its factorization.

91097778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9330.

The product of its (nonzero) digits is 222264, while the sum is 48.

The square root of 91097778 is about 9544.5155979756. The cubic root of 91097778 is about 449.9551856607.

The spelling of 91097778 in words is "ninety-one million, ninety-seven thousand, seven hundred seventy-eight".