20684761 has 2 divisors, whose sum is σ = 20684762. Its totient is φ = 20684760.

The previous prime is 20684717. The next prime is 20684771. The reversal of 20684761 is 16748602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18011536 + 2673225 = 4244^2 + 1635^2 .

It is a cyclic number.

It is not a de Polignac number, because 20684761 - 2⁹ = 20684249 is a prime.

It is not a weakly prime, because it can be changed into another prime (20684771) 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, 10342380 + 10342381.

It is an arithmetic number, because the mean of its divisors is an integer number (10342381).

Almost surely, 2^20684761 is an apocalyptic number.

It is an amenable number.

20684761 is a deficient number, since it is larger than the sum of its proper divisors (1).

20684761 is an equidigital number, since it uses as much as digits as its factorization.

20684761 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16128, while the sum is 34.

The square root of 20684761 is about 4548.0502415870. The cubic root of 20684761 is about 274.5049429382.

The spelling of 20684761 in words is "twenty million, six hundred eighty-four thousand, seven hundred sixty-one".