91091090 has 8 divisors (see below), whose sum is σ = 163963980. Its totient is φ = 36436432.

The previous prime is 91091081. The next prime is 91091129. The reversal of 91091090 is 9019019.

It can be written as a sum of positive squares in 2 ways, for example, as 88190881 + 2900209 = 9391^2 + 1703^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4554545 + ... + 4554564.

Almost surely, 2^91091090 is an apocalyptic number.

91091090 is a deficient number, since it is larger than the sum of its proper divisors (72872890).

91091090 is a wasteful number, since it uses less digits than its factorization.

91091090 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9109116.

The product of its (nonzero) digits is 729, while the sum is 29.

The square root of 91091090 is about 9544.1652332721. The cubic root of 91091090 is about 449.9441741446.

The spelling of 91091090 in words is "ninety-one million, ninety-one thousand, ninety".