91218229 has 4 divisors (see below), whose sum is σ = 91745676. Its totient is φ = 90690784.

The previous prime is 91218227. The next prime is 91218263. The reversal of 91218229 is 92281219.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 50552100 + 40666129 = 7110^2 + 6377^2 .

It is a cyclic number.

It is not a de Polignac number, because 91218229 - 2¹ = 91218227 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 91218194 and 91218203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91218227) 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, 263464 + ... + 263809.

It is an arithmetic number, because the mean of its divisors is an integer number (22936419).

Almost surely, 2^91218229 is an apocalyptic number.

It is an amenable number.

91218229 is a deficient number, since it is larger than the sum of its proper divisors (527447).

91218229 is a wasteful number, since it uses less digits than its factorization.

91218229 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 527446.

The product of its digits is 5184, while the sum is 34.

The square root of 91218229 is about 9550.8234723504. The cubic root of 91218229 is about 450.1534110686.

The spelling of 91218229 in words is "ninety-one million, two hundred eighteen thousand, two hundred twenty-nine".