20685361 has 4 divisors (see below), whose sum is σ = 21189924. Its totient is φ = 20180800.

The previous prime is 20685337. The next prime is 20685367. The reversal of 20685361 is 16358602.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5130225 + 15555136 = 2265^2 + 3944^2 .

It is a cyclic number.

It is not a de Polignac number, because 20685361 - 2¹³ = 20677169 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20685367) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 252220 + ... + 252301.

It is an arithmetic number, because the mean of its divisors is an integer number (5297481).

Almost surely, 2^20685361 is an apocalyptic number.

It is an amenable number.

20685361 is a deficient number, since it is larger than the sum of its proper divisors (504563).

20685361 is an equidigital number, since it uses as much as digits as its factorization.

20685361 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 504562.

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 20685361 is about 4548.1162034407. The cubic root of 20685361 is about 274.5075970881.

The spelling of 20685361 in words is "twenty million, six hundred eighty-five thousand, three hundred sixty-one".