221840541 has 24 divisors (see below), whose sum is σ = 348520536. Its totient is φ = 135158400.

The previous prime is 221840539. The next prime is 221840581. The reversal of 221840541 is 145048122.

221840541 is a `hidden beast` number, since 2 + 218 + 405 + 41 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 129276900 + 92563641 = 11370^2 + 9621^2 .

It is not a de Polignac number, because 221840541 - 2¹ = 221840539 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221840581) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 2431 + ... + 21203.

It is an arithmetic number, because the mean of its divisors is an integer number (14521689).

Almost surely, 2^221840541 is an apocalyptic number.

It is an amenable number.

221840541 is a deficient number, since it is larger than the sum of its proper divisors (126679995).

221840541 is a wasteful number, since it uses less digits than its factorization.

221840541 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18893 (or 18890 counting only the distinct ones).

The product of its (nonzero) digits is 2560, while the sum is 27.

The square root of 221840541 is about 14894.3123708347. The cubic root of 221840541 is about 605.3598851440.

Adding to 221840541 its reverse (145048122), we get a palindrome (366888663).

The spelling of 221840541 in words is "two hundred twenty-one million, eight hundred forty thousand, five hundred forty-one".