20688869 has 2 divisors, whose sum is σ = 20688870. Its totient is φ = 20688868.

The previous prime is 20688827. The next prime is 20688907. The reversal of 20688869 is 96888602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13468900 + 7219969 = 3670^2 + 2687^2 .

It is a cyclic number.

It is not a de Polignac number, because 20688869 - 2¹⁶ = 20623333 is a prime.

It is a super-2 number, since 2×20688869² = 856058600998322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20682869) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10344434 + 10344435.

It is an arithmetic number, because the mean of its divisors is an integer number (10344435).

Almost surely, 2^20688869 is an apocalyptic number.

It is an amenable number.

20688869 is a deficient number, since it is larger than the sum of its proper divisors (1).

20688869 is an equidigital number, since it uses as much as digits as its factorization.

20688869 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 331776, while the sum is 47.

The square root of 20688869 is about 4548.5018412660. The cubic root of 20688869 is about 274.5231139911.

The spelling of 20688869 in words is "twenty million, six hundred eighty-eight thousand, eight hundred sixty-nine".