221666155110497 has 2 divisors, whose sum is σ = 221666155110498. Its totient is φ = 221666155110496.

The previous prime is 221666155110473. The next prime is 221666155110503. The reversal of 221666155110497 is 794011551666122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 221239326781456 + 426828329041 = 14874116^2 + 653321^2 .

It is a cyclic number.

It is not a de Polignac number, because 221666155110497 - 2¹⁸ = 221666154848353 is a prime.

It is not a weakly prime, because it can be changed into another prime (221666155110467) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110833077555248 + 110833077555249.

It is an arithmetic number, because the mean of its divisors is an integer number (110833077555249).

Almost surely, 2^{221666155110497} is an apocalyptic number.

It is an amenable number.

221666155110497 is a deficient number, since it is larger than the sum of its proper divisors (1).

221666155110497 is an equidigital number, since it uses as much as digits as its factorization.

221666155110497 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5443200, while the sum is 56.

The spelling of 221666155110497 in words is "two hundred twenty-one trillion, six hundred sixty-six billion, one hundred fifty-five million, one hundred ten thousand, four hundred ninety-seven".