43620221 has 4 divisors (see below), whose sum is σ = 44070012. Its totient is φ = 43170432.

The previous prime is 43620211. The next prime is 43620229. The reversal of 43620221 is 12202634.

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 30580900 + 13039321 = 5530^2 + 3611^2 .

It is not a de Polignac number, because 43620221 - 2¹⁰ = 43619197 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 43620193 and 43620202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (43620229) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 224750 + ... + 224943.

It is an arithmetic number, because the mean of its divisors is an integer number (11017503).

Almost surely, 2^43620221 is an apocalyptic number.

It is an amenable number.

43620221 is a deficient number, since it is larger than the sum of its proper divisors (449791).

43620221 is an equidigital number, since it uses as much as digits as its factorization.

43620221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 449790.

The product of its (nonzero) digits is 576, while the sum is 20.

The square root of 43620221 is about 6604.5606212677. The cubic root of 43620221 is about 352.0161757589.

Adding to 43620221 its reverse (12202634), we get a palindrome (55822855).

The spelling of 43620221 in words is "forty-three million, six hundred twenty thousand, two hundred twenty-one".