115221809 has 4 divisors (see below), whose sum is σ = 115247616. Its totient is φ = 115196004.

The previous prime is 115221797. The next prime is 115221839. The reversal of 115221809 is 908122511.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 908122511 = 53 ⋅17134387.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-115221809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (115221839) 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, 4289 + ... + 15774.

It is an arithmetic number, because the mean of its divisors is an integer number (28811904).

Almost surely, 2^115221809 is an apocalyptic number.

It is an amenable number.

115221809 is a deficient number, since it is larger than the sum of its proper divisors (25807).

115221809 is an equidigital number, since it uses as much as digits as its factorization.

115221809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25806.

The product of its (nonzero) digits is 1440, while the sum is 29.

The square root of 115221809 is about 10734.1422107218. The cubic root of 115221809 is about 486.6068629731.

It can be divided in two parts, 11522 and 1809, that added together give a palindrome (13331).

The spelling of 115221809 in words is "one hundred fifteen million, two hundred twenty-one thousand, eight hundred nine".