20825393681 has 2 divisors, whose sum is σ = 20825393682. Its totient is φ = 20825393680.

The previous prime is 20825393663. The next prime is 20825393713. The reversal of 20825393681 is 18639352802.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19258500625 + 1566893056 = 138775^2 + 39584^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20825393681 is a prime.

It is a super-2 number, since 2×20825393681² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20825393651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10412696840 + 10412696841.

It is an arithmetic number, because the mean of its divisors is an integer number (10412696841).

Almost surely, 2^20825393681 is an apocalyptic number.

It is an amenable number.

20825393681 is a deficient number, since it is larger than the sum of its proper divisors (1).

20825393681 is an equidigital number, since it uses as much as digits as its factorization.

20825393681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 622080, while the sum is 47.

The spelling of 20825393681 in words is "twenty billion, eight hundred twenty-five million, three hundred ninety-three thousand, six hundred eighty-one".