20681351 has 2 divisors, whose sum is σ = 20681352. Its totient is φ = 20681350.

The previous prime is 20681327. The next prime is 20681369. The reversal of 20681351 is 15318602.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20681351 - 2¹⁴ = 20664967 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20681351.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20681251) 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, 10340675 + 10340676.

It is an arithmetic number, because the mean of its divisors is an integer number (10340676).

Almost surely, 2^20681351 is an apocalyptic number.

20681351 is a deficient number, since it is larger than the sum of its proper divisors (1).

20681351 is an equidigital number, since it uses as much as digits as its factorization.

20681351 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1440, while the sum is 26.

The square root of 20681351 is about 4547.6753402150. The cubic root of 20681351 is about 274.4898575443.

Adding to 20681351 its reverse (15318602), we get a palindrome (35999953).

The spelling of 20681351 in words is "twenty million, six hundred eighty-one thousand, three hundred fifty-one".