20685213 has 20 divisors (see below), whose sum is σ = 31049568. Its totient is φ = 13723560.

The previous prime is 20685199. The next prime is 20685227. The reversal of 20685213 is 31258602.

It is an interprime number because it is at equal distance from previous prime (20685199) and next prime (20685227).

It is not a de Polignac number, because 20685213 - 2⁸ = 20684957 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20685013) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 20818 + ... + 21788.

Almost surely, 2^20685213 is an apocalyptic number.

It is an amenable number.

20685213 is a deficient number, since it is larger than the sum of its proper divisors (10364355).

20685213 is an equidigital number, since it uses as much as digits as its factorization.

20685213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1246 (or 1237 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The square root of 20685213 is about 4548.0999329390. The cubic root of 20685213 is about 274.5069424026.

The spelling of 20685213 in words is "twenty million, six hundred eighty-five thousand, two hundred thirteen".