661663365053 has 2 divisors, whose sum is σ = 661663365054. Its totient is φ = 661663365052.

The previous prime is 661663365043. The next prime is 661663365061. The reversal of 661663365053 is 350563366166.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 617987798884 + 43675566169 = 786122^2 + 208987^2 .

It is a cyclic number.

It is not a de Polignac number, because 661663365053 - 2⁴ = 661663365037 is a prime.

It is a super-3 number, since 3×661663365053³ (a number of 36 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 661663364992 and 661663365010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661663365043) 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, 330831682526 + 330831682527.

It is an arithmetic number, because the mean of its divisors is an integer number (330831682527).

Almost surely, 2^661663365053 is an apocalyptic number.

It is an amenable number.

661663365053 is a deficient number, since it is larger than the sum of its proper divisors (1).

661663365053 is an equidigital number, since it uses as much as digits as its factorization.

661663365053 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5248800, while the sum is 50.

The spelling of 661663365053 in words is "six hundred sixty-one billion, six hundred sixty-three million, three hundred sixty-five thousand, fifty-three".