20857871597 has 2 divisors, whose sum is σ = 20857871598. Its totient is φ = 20857871596.

The previous prime is 20857871561. The next prime is 20857871599. The reversal of 20857871597 is 79517875802.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20422982281 + 434889316 = 142909^2 + 20854^2 .

It is a cyclic number.

It is not a de Polignac number, because 20857871597 - 2⁶ = 20857871533 is a prime.

Together with 20857871599, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20857871599) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10428935798 + 10428935799.

It is an arithmetic number, because the mean of its divisors is an integer number (10428935799).

Almost surely, 2^20857871597 is an apocalyptic number.

It is an amenable number.

20857871597 is a deficient number, since it is larger than the sum of its proper divisors (1).

20857871597 is an equidigital number, since it uses as much as digits as its factorization.

20857871597 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9878400, while the sum is 59.

The spelling of 20857871597 in words is "twenty billion, eight hundred fifty-seven million, eight hundred seventy-one thousand, five hundred ninety-seven".