20639398757 has 2 divisors, whose sum is σ = 20639398758. Its totient is φ = 20639398756.

The previous prime is 20639398727. The next prime is 20639398771. The reversal of 20639398757 is 75789393602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20128231876 + 511166881 = 141874^2 + 22609^2 .

It is a cyclic number.

It is not a de Polignac number, because 20639398757 - 2⁶ = 20639398693 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20639398696 and 20639398705.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20639398727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10319699378 + 10319699379.

It is an arithmetic number, because the mean of its divisors is an integer number (10319699379).

Almost surely, 2^20639398757 is an apocalyptic number.

It is an amenable number.

20639398757 is a deficient number, since it is larger than the sum of its proper divisors (1).

20639398757 is an equidigital number, since it uses as much as digits as its factorization.

20639398757 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 17146080, while the sum is 59.

The spelling of 20639398757 in words is "twenty billion, six hundred thirty-nine million, three hundred ninety-eight thousand, seven hundred fifty-seven".