20708861388497 has 2 divisors, whose sum is σ = 20708861388498. Its totient is φ = 20708861388496.

The previous prime is 20708861388493. The next prime is 20708861388629. The reversal of 20708861388497 is 79488316880702.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15703435115536 + 5005426272961 = 3962756^2 + 2237281^2 .

It is a cyclic number.

It is not a de Polignac number, because 20708861388497 - 2² = 20708861388493 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20708861388497.

It is not a weakly prime, because it can be changed into another prime (20708861388493) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10354430694248 + 10354430694249.

It is an arithmetic number, because the mean of its divisors is an integer number (10354430694249).

Almost surely, 2^{20708861388497} is an apocalyptic number.

It is an amenable number.

20708861388497 is a deficient number, since it is larger than the sum of its proper divisors (1).

20708861388497 is an equidigital number, since it uses as much as digits as its factorization.

20708861388497 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 260112384, while the sum is 71.

The spelling of 20708861388497 in words is "twenty trillion, seven hundred eight billion, eight hundred sixty-one million, three hundred eighty-eight thousand, four hundred ninety-seven".