91811228 has 12 divisors (see below), whose sum is σ = 161091840. Its totient is φ = 45784992.

The previous prime is 91811227. The next prime is 91811261. The reversal of 91811228 is 82211819.

It is a junction number, because it is equal to n+sod(n) for n = 91811194 and 91811203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91811227) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 28433 + ... + 31496.

It is an arithmetic number, because the mean of its divisors is an integer number (13424320).

Almost surely, 2^91811228 is an apocalyptic number.

It is an amenable number.

91811228 is a deficient number, since it is larger than the sum of its proper divisors (69280612).

91811228 is a wasteful number, since it uses less digits than its factorization.

91811228 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60316 (or 60314 counting only the distinct ones).

The product of its digits is 2304, while the sum is 32.

The square root of 91811228 is about 9581.8175728825. The cubic root of 91811228 is about 451.1267697053.

The spelling of 91811228 in words is "ninety-one million, eight hundred eleven thousand, two hundred twenty-eight".