221556635441 has 2 divisors, whose sum is σ = 221556635442. Its totient is φ = 221556635440.

The previous prime is 221556635381. The next prime is 221556635459. The reversal of 221556635441 is 144536655122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 172726684816 + 48829950625 = 415604^2 + 220975^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221556635441 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 221556635392 and 221556635401.

It is not a weakly prime, because it can be changed into another prime (221556637441) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110778317720 + 110778317721.

It is an arithmetic number, because the mean of its divisors is an integer number (110778317721).

Almost surely, 2^221556635441 is an apocalyptic number.

It is an amenable number.

221556635441 is a deficient number, since it is larger than the sum of its proper divisors (1).

221556635441 is an equidigital number, since it uses as much as digits as its factorization.

221556635441 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 864000, while the sum is 44.

The spelling of 221556635441 in words is "two hundred twenty-one billion, five hundred fifty-six million, six hundred thirty-five thousand, four hundred forty-one".