221868505 has 4 divisors (see below), whose sum is σ = 266242212. Its totient is φ = 177494800.

The previous prime is 221868503. The next prime is 221868509. The reversal of 221868505 is 505868122.

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 88604569 + 133263936 = 9413^2 + 11544^2 .

It is not a de Polignac number, because 221868505 - 2¹ = 221868503 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221868503) 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, 22186846 + ... + 22186855.

It is an arithmetic number, because the mean of its divisors is an integer number (66560553).

Almost surely, 2^221868505 is an apocalyptic number.

It is an amenable number.

221868505 is a deficient number, since it is larger than the sum of its proper divisors (44373707).

221868505 is an equidigital number, since it uses as much as digits as its factorization.

221868505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44373706.

The product of its (nonzero) digits is 38400, while the sum is 37.

The square root of 221868505 is about 14895.2510888538. The cubic root of 221868505 is about 605.3853201892.

The spelling of 221868505 in words is "two hundred twenty-one million, eight hundred sixty-eight thousand, five hundred five".