20685601 has 2 divisors, whose sum is σ = 20685602. Its totient is φ = 20685600.

The previous prime is 20685589. The next prime is 20685629. The reversal of 20685601 is 10658602.

It is an a-pointer prime, because the next prime (20685629) can be obtained adding 20685601 to its sum of digits (28).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18792225 + 1893376 = 4335^2 + 1376^2 .

It is a cyclic number.

It is not a de Polignac number, because 20685601 - 2⁵ = 20685569 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20685601.

It is not a weakly prime, because it can be changed into another prime (20685631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10342800 + 10342801.

It is an arithmetic number, because the mean of its divisors is an integer number (10342801).

Almost surely, 2^20685601 is an apocalyptic number.

It is an amenable number.

20685601 is a deficient number, since it is larger than the sum of its proper divisors (1).

20685601 is an equidigital number, since it uses as much as digits as its factorization.

20685601 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2880, while the sum is 28.

The square root of 20685601 is about 4548.1425879143. The cubic root of 20685601 is about 274.5086587338.

The spelling of 20685601 in words is "twenty million, six hundred eighty-five thousand, six hundred one".