20857713493 has 2 divisors, whose sum is σ = 20857713494. Its totient is φ = 20857713492.

The previous prime is 20857713451. The next prime is 20857713509. The reversal of 20857713493 is 39431775802.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18280932849 + 2576780644 = 135207^2 + 50762^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20857713493 is a prime.

It is a super-2 number, since 2×20857713493² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20857713403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10428856746 + 10428856747.

It is an arithmetic number, because the mean of its divisors is an integer number (10428856747).

Almost surely, 2^20857713493 is an apocalyptic number.

It is an amenable number.

20857713493 is a deficient number, since it is larger than the sum of its proper divisors (1).

20857713493 is an equidigital number, since it uses as much as digits as its factorization.

20857713493 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1270080, while the sum is 49.

The spelling of 20857713493 in words is "twenty billion, eight hundred fifty-seven million, seven hundred thirteen thousand, four hundred ninety-three".