43545221 has 2 divisors, whose sum is σ = 43545222. Its totient is φ = 43545220.

The previous prime is 43545217. The next prime is 43545247. The reversal of 43545221 is 12254534.

It is a happy number.

It is an a-pointer prime, because the next prime (43545247) can be obtained adding 43545221 to its sum of digits (26).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 42432196 + 1113025 = 6514^2 + 1055^2 .

It is a cyclic number.

It is not a de Polignac number, because 43545221 - 2² = 43545217 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (43545251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21772610 + 21772611.

It is an arithmetic number, because the mean of its divisors is an integer number (21772611).

Almost surely, 2^43545221 is an apocalyptic number.

It is an amenable number.

43545221 is a deficient number, since it is larger than the sum of its proper divisors (1).

43545221 is an equidigital number, since it uses as much as digits as its factorization.

43545221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4800, while the sum is 26.

The square root of 43545221 is about 6598.8802838057. The cubic root of 43545221 is about 351.8143094506.

Adding to 43545221 its reverse (12254534), we get a palindrome (55799755).

The spelling of 43545221 in words is "forty-three million, five hundred forty-five thousand, two hundred twenty-one".