20988460657 has 2 divisors, whose sum is σ = 20988460658. Its totient is φ = 20988460656.

The previous prime is 20988460583. The next prime is 20988460673. The reversal of 20988460657 is 75606488902.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15436571536 + 5551889121 = 124244^2 + 74511^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20988460657 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20988460598 and 20988460607.

It is not a weakly prime, because it can be changed into another prime (20688460657) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10494230328 + 10494230329.

It is an arithmetic number, because the mean of its divisors is an integer number (10494230329).

Almost surely, 2^20988460657 is an apocalyptic number.

It is an amenable number.

20988460657 is a deficient number, since it is larger than the sum of its proper divisors (1).

20988460657 is an equidigital number, since it uses as much as digits as its factorization.

20988460657 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5806080, while the sum is 55.

The spelling of 20988460657 in words is "twenty billion, nine hundred eighty-eight million, four hundred sixty thousand, six hundred fifty-seven".