221355545 has 4 divisors (see below), whose sum is σ = 265626660. Its totient is φ = 177084432.

The previous prime is 221355509. The next prime is 221355553. The reversal of 221355545 is 545553122.

221355545 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 97456384 + 123899161 = 9872^2 + 11131^2 .

It is a cyclic number.

It is not a de Polignac number, because 221355545 - 2⁶ = 221355481 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22135550 + ... + 22135559.

It is an arithmetic number, because the mean of its divisors is an integer number (66406665).

Almost surely, 2^221355545 is an apocalyptic number.

It is an amenable number.

221355545 is a deficient number, since it is larger than the sum of its proper divisors (44271115).

221355545 is an equidigital number, since it uses as much as digits as its factorization.

221355545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44271114.

The product of its digits is 30000, while the sum is 32.

The square root of 221355545 is about 14878.0222139907. The cubic root of 221355545 is about 604.9184098702.

The spelling of 221355545 in words is "two hundred twenty-one million, three hundred fifty-five thousand, five hundred forty-five".