505406165657 has 2 divisors, whose sum is σ = 505406165658. Its totient is φ = 505406165656.

The previous prime is 505406165651. The next prime is 505406165659. The reversal of 505406165657 is 756561604505.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 325982760601 + 179423405056 = 570949^2 + 423584^2 .

It is a cyclic number.

It is not a de Polignac number, because 505406165657 - 2²⁰ = 505405117081 is a prime.

It is a super-2 number, since 2×505406165657² (a number of 24 digits) contains 22 as substring.

Together with 505406165659, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (505406165651) 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, 252703082828 + 252703082829.

It is an arithmetic number, because the mean of its divisors is an integer number (252703082829).

Almost surely, 2^505406165657 is an apocalyptic number.

It is an amenable number.

505406165657 is a deficient number, since it is larger than the sum of its proper divisors (1).

505406165657 is an equidigital number, since it uses as much as digits as its factorization.

505406165657 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3780000, while the sum is 50.

The spelling of 505406165657 in words is "five hundred five billion, four hundred six million, one hundred sixty-five thousand, six hundred fifty-seven".