221641633 has 2 divisors, whose sum is σ = 221641634. Its totient is φ = 221641632.

The previous prime is 221641621. The next prime is 221641643. The reversal of 221641633 is 336146122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 127396369 + 94245264 = 11287^2 + 9708^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221641633 is a prime.

It is equal to p_12207925 and since 221641633 and 12207925 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (221641643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110820816 + 110820817.

It is an arithmetic number, because the mean of its divisors is an integer number (110820817).

Almost surely, 2^221641633 is an apocalyptic number.

It is an amenable number.

221641633 is a deficient number, since it is larger than the sum of its proper divisors (1).

221641633 is an equidigital number, since it uses as much as digits as its factorization.

221641633 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5184, while the sum is 28.

The square root of 221641633 is about 14887.6335594345. The cubic root of 221641633 is about 605.1789039021.

Adding to 221641633 its reverse (336146122), we get a palindrome (557787755).

The spelling of 221641633 in words is "two hundred twenty-one million, six hundred forty-one thousand, six hundred thirty-three".