221545255 has 4 divisors (see below), whose sum is σ = 265854312. Its totient is φ = 177236200.

The previous prime is 221545249. The next prime is 221545283. The reversal of 221545255 is 552545122.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 552545122 = 2 ⋅276272561.

It is not a de Polignac number, because 221545255 - 2²⁵ = 187990823 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22154521 + ... + 22154530.

It is an arithmetic number, because the mean of its divisors is an integer number (66463578).

Almost surely, 2^221545255 is an apocalyptic number.

221545255 is a deficient number, since it is larger than the sum of its proper divisors (44309057).

221545255 is an equidigital number, since it uses as much as digits as its factorization.

221545255 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44309056.

The product of its digits is 20000, while the sum is 31.

The square root of 221545255 is about 14884.3963599469. The cubic root of 221545255 is about 605.0911731093.

The spelling of 221545255 in words is "two hundred twenty-one million, five hundred forty-five thousand, two hundred fifty-five".