20685216 has 24 divisors (see below), whose sum is σ = 54298944. Its totient is φ = 6895040.

The previous prime is 20685199. The next prime is 20685227. The reversal of 20685216 is 61258602.

It is a tau number, because it is divible by the number of its divisors (24).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 107640 + ... + 107831.

It is an arithmetic number, because the mean of its divisors is an integer number (2262456).

Almost surely, 2^20685216 is an apocalyptic number.

It is an amenable number.

20685216 is an abundant number, since it is smaller than the sum of its proper divisors (33613728).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20685216 is a wasteful number, since it uses less digits than its factorization.

20685216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 215484 (or 215476 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 30.

The square root of 20685216 is about 4548.1002627471. The cubic root of 20685216 is about 274.5069556733.

The spelling of 20685216 in words is "twenty million, six hundred eighty-five thousand, two hundred sixteen".