20047198657 has 2 divisors, whose sum is σ = 20047198658. Its totient is φ = 20047198656.

The previous prime is 20047198571. The next prime is 20047198667. The reversal of 20047198657 is 75689174002.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13283945536 + 6763253121 = 115256^2 + 82239^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20047198657 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20047198657.

It is not a weakly prime, because it can be changed into another prime (20047198667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10023599328 + 10023599329.

It is an arithmetic number, because the mean of its divisors is an integer number (10023599329).

Almost surely, 2^20047198657 is an apocalyptic number.

It is an amenable number.

20047198657 is a deficient number, since it is larger than the sum of its proper divisors (1).

20047198657 is an equidigital number, since it uses as much as digits as its factorization.

20047198657 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 846720, while the sum is 49.

The spelling of 20047198657 in words is "twenty billion, forty-seven million, one hundred ninety-eight thousand, six hundred fifty-seven".