43555221 has 6 divisors (see below), whose sum is σ = 62913110. Its totient is φ = 29036808.

The previous prime is 43555219. The next prime is 43555223. The reversal of 43555221 is 12255534.

It is a happy number.

43555221 is a `hidden beast` number, since 435 + 5 + 5 + 221 = 666.

It is an interprime number because it is at equal distance from previous prime (43555219) and next prime (43555223).

It can be written as a sum of positive squares in only one way, i.e., 34644996 + 8910225 = 5886^2 + 2985^2 .

It is not a de Polignac number, because 43555221 - 2¹ = 43555219 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (43555223) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2419726 + ... + 2419743.

Almost surely, 2^43555221 is an apocalyptic number.

It is an amenable number.

43555221 is a deficient number, since it is larger than the sum of its proper divisors (19357889).

43555221 is a wasteful number, since it uses less digits than its factorization.

43555221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4839475 (or 4839472 counting only the distinct ones).

The product of its digits is 6000, while the sum is 27.

The square root of 43555221 is about 6599.6379446148. The cubic root of 43555221 is about 351.8412383438.

The spelling of 43555221 in words is "forty-three million, five hundred fifty-five thousand, two hundred twenty-one".