221143621 has 2 divisors, whose sum is σ = 221143622. Its totient is φ = 221143620.

The previous prime is 221143609. The next prime is 221143661. The reversal of 221143621 is 126341122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 131102500 + 90041121 = 11450^2 + 9489^2 .

It is a cyclic number.

It is not a de Polignac number, because 221143621 - 2¹³ = 221135429 is a prime.

It is a super-2 number, since 2×221143621² = 97809002217983282, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 221143592 and 221143601.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221143661) 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 as a sum of consecutive naturals, namely, 110571810 + 110571811.

It is an arithmetic number, because the mean of its divisors is an integer number (110571811).

Almost surely, 2^221143621 is an apocalyptic number.

It is an amenable number.

221143621 is a deficient number, since it is larger than the sum of its proper divisors (1).

221143621 is an equidigital number, since it uses as much as digits as its factorization.

221143621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 576, while the sum is 22.

The square root of 221143621 is about 14870.8984597434. The cubic root of 221143621 is about 604.7253002399.

Adding to 221143621 its reverse (126341122), we get a palindrome (347484743).

The spelling of 221143621 in words is "two hundred twenty-one million, one hundred forty-three thousand, six hundred twenty-one".