221532643 has 4 divisors (see below), whose sum is σ = 221571288. Its totient is φ = 221494000.

The previous prime is 221532637. The next prime is 221532677. The reversal of 221532643 is 346235122.

221532643 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 is a cyclic number.

It is not a de Polignac number, because 221532643 - 2¹³ = 221524451 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221532613) 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, 8821 + ... + 22822.

It is an arithmetic number, because the mean of its divisors is an integer number (55392822).

Almost surely, 2^221532643 is an apocalyptic number.

221532643 is a deficient number, since it is larger than the sum of its proper divisors (38645).

221532643 is an equidigital number, since it uses as much as digits as its factorization.

221532643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38644.

The product of its digits is 8640, while the sum is 28.

The square root of 221532643 is about 14883.9726887683. The cubic root of 221532643 is about 605.0796907981.

Adding to 221532643 its reverse (346235122), we get a palindrome (567767765).

The spelling of 221532643 in words is "two hundred twenty-one million, five hundred thirty-two thousand, six hundred forty-three".