91091020 has 24 divisors (see below), whose sum is σ = 197463168. Its totient is φ = 35260800.

The previous prime is 91090957. The next prime is 91091023. The reversal of 91091020 is 2019019.

It is a junction number, because it is equal to n+sod(n) for n = 91090982 and 91091000.

It is not an unprimeable number, because it can be changed into a prime (91091023) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 72841 + ... + 74080.

It is an arithmetic number, because the mean of its divisors is an integer number (8227632).

Almost surely, 2^91091020 is an apocalyptic number.

It is an amenable number.

91091020 is an abundant number, since it is smaller than the sum of its proper divisors (106372148).

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

91091020 is a wasteful number, since it uses less digits than its factorization.

91091020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 146961 (or 146959 counting only the distinct ones).

The product of its (nonzero) digits is 162, while the sum is 22.

The square root of 91091020 is about 9544.1615661094. The cubic root of 91091020 is about 449.9440588897.

The spelling of 91091020 in words is "ninety-one million, ninety-one thousand, twenty".