20681369 has 2 divisors, whose sum is σ = 20681370. Its totient is φ = 20681368.

The previous prime is 20681351. The next prime is 20681399. The reversal of 20681369 is 96318602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18593344 + 2088025 = 4312^2 + 1445^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20681369 is a prime.

It is a super-2 number, since 2×20681369² = 855438047428322, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20681399) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10340684 + 10340685.

It is an arithmetic number, because the mean of its divisors is an integer number (10340685).

Almost surely, 2^20681369 is an apocalyptic number.

It is an amenable number.

20681369 is a deficient number, since it is larger than the sum of its proper divisors (1).

20681369 is an equidigital number, since it uses as much as digits as its factorization.

20681369 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15552, while the sum is 35.

The square root of 20681369 is about 4547.6773192477. The cubic root of 20681369 is about 274.4899371783.

The spelling of 20681369 in words is "twenty million, six hundred eighty-one thousand, three hundred sixty-nine".