221605557137 has 2 divisors, whose sum is σ = 221605557138. Its totient is φ = 221605557136.

The previous prime is 221605557077. The next prime is 221605557157. The reversal of 221605557137 is 731755506122.

221605557137 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 114566002576 + 107039554561 = 338476^2 + 327169^2 .

It is a cyclic number.

It is not a de Polignac number, because 221605557137 - 2¹² = 221605553041 is a prime.

It is not a weakly prime, because it can be changed into another prime (221605557157) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110802778568 + 110802778569.

It is an arithmetic number, because the mean of its divisors is an integer number (110802778569).

Almost surely, 2^221605557137 is an apocalyptic number.

It is an amenable number.

221605557137 is a deficient number, since it is larger than the sum of its proper divisors (1).

221605557137 is an equidigital number, since it uses as much as digits as its factorization.

221605557137 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 441000, while the sum is 44.

The spelling of 221605557137 in words is "two hundred twenty-one billion, six hundred five million, five hundred fifty-seven thousand, one hundred thirty-seven".