20421130255657 has 2 divisors, whose sum is σ = 20421130255658. Its totient is φ = 20421130255656.

The previous prime is 20421130255627. The next prime is 20421130255699. The reversal of 20421130255657 is 75655203112402.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14312269320336 + 6108860935321 = 3783156^2 + 2471611^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20421130255657 is a prime.

It is not a weakly prime, because it can be changed into another prime (20421130255627) 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, 10210565127828 + 10210565127829.

It is an arithmetic number, because the mean of its divisors is an integer number (10210565127829).

Almost surely, 2^{20421130255657} is an apocalyptic number.

It is an amenable number.

20421130255657 is a deficient number, since it is larger than the sum of its proper divisors (1).

20421130255657 is an equidigital number, since it uses as much as digits as its factorization.

20421130255657 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 504000, while the sum is 43.

The spelling of 20421130255657 in words is "twenty trillion, four hundred twenty-one billion, one hundred thirty million, two hundred fifty-five thousand, six hundred fifty-seven".