221329555 has 4 divisors (see below), whose sum is σ = 265595472. Its totient is φ = 177063640.

The previous prime is 221329531. The next prime is 221329567. The reversal of 221329555 is 555923122.

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

It is not a de Polignac number, because 221329555 - 2¹³ = 221321363 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 221329555.

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, 22132951 + ... + 22132960.

It is an arithmetic number, because the mean of its divisors is an integer number (66398868).

Almost surely, 2^221329555 is an apocalyptic number.

221329555 is a deficient number, since it is larger than the sum of its proper divisors (44265917).

221329555 is an equidigital number, since it uses as much as digits as its factorization.

221329555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44265916.

The product of its digits is 27000, while the sum is 34.

The square root of 221329555 is about 14877.1487523652. The cubic root of 221329555 is about 604.8947338654.

The spelling of 221329555 in words is "two hundred twenty-one million, three hundred twenty-nine thousand, five hundred fifty-five".