20648434657 has 2 divisors, whose sum is σ = 20648434658. Its totient is φ = 20648434656.

The previous prime is 20648434627. The next prime is 20648434663. The reversal of 20648434657 is 75643484602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15005270016 + 5643164641 = 122496^2 + 75121^2 .

It is a cyclic number.

It is not a de Polignac number, because 20648434657 - 2²⁷ = 20514216929 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20648434657.

It is not a weakly prime, because it can be changed into another prime (20648434627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10324217328 + 10324217329.

It is an arithmetic number, because the mean of its divisors is an integer number (10324217329).

Almost surely, 2^20648434657 is an apocalyptic number.

It is an amenable number.

20648434657 is a deficient number, since it is larger than the sum of its proper divisors (1).

20648434657 is an equidigital number, since it uses as much as digits as its factorization.

20648434657 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3870720, while the sum is 49.

The spelling of 20648434657 in words is "twenty billion, six hundred forty-eight million, four hundred thirty-four thousand, six hundred fifty-seven".