20857190789 has 2 divisors, whose sum is σ = 20857190790. Its totient is φ = 20857190788.

The previous prime is 20857190759. The next prime is 20857190797. The reversal of 20857190789 is 98709175802.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19394740225 + 1462450564 = 139265^2 + 38242^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20857190789 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20857190749) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10428595394 + 10428595395.

It is an arithmetic number, because the mean of its divisors is an integer number (10428595395).

Almost surely, 2^20857190789 is an apocalyptic number.

It is an amenable number.

20857190789 is a deficient number, since it is larger than the sum of its proper divisors (1).

20857190789 is an equidigital number, since it uses as much as digits as its factorization.

20857190789 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2540160, while the sum is 56.

The spelling of 20857190789 in words is "twenty billion, eight hundred fifty-seven million, one hundred ninety thousand, seven hundred eighty-nine".