221538633 has 4 divisors (see below), whose sum is σ = 295384848. Its totient is φ = 147692420.

The previous prime is 221538619. The next prime is 221538659. The reversal of 221538633 is 336835122.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 221538633 - 2⁸ = 221538377 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 221538594 and 221538603.

It is not an unprimeable number, because it can be changed into a prime (221538133) 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 3 ways as a sum of consecutive naturals, for example, 36923103 + ... + 36923108.

It is an arithmetic number, because the mean of its divisors is an integer number (73846212).

Almost surely, 2^221538633 is an apocalyptic number.

It is an amenable number.

221538633 is a deficient number, since it is larger than the sum of its proper divisors (73846215).

221538633 is an equidigital number, since it uses as much as digits as its factorization.

221538633 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73846214.

The product of its digits is 25920, while the sum is 33.

The square root of 221538633 is about 14884.1739105669. The cubic root of 221538633 is about 605.0851443129.

The spelling of 221538633 in words is "two hundred twenty-one million, five hundred thirty-eight thousand, six hundred thirty-three".