20857218 has 8 divisors (see below), whose sum is σ = 41714448. Its totient is φ = 6952404.

The previous prime is 20857217. The next prime is 20857247. The reversal of 20857218 is 81275802.

It is a sphenic number, since it is the product of 3 distinct primes.

20857218 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (20857211) 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, 1738096 + ... + 1738107.

It is an arithmetic number, because the mean of its divisors is an integer number (5214306).

Almost surely, 2^20857218 is an apocalyptic number.

20857218 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

20857218 is a wasteful number, since it uses less digits than its factorization.

20857218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3476208.

The product of its (nonzero) digits is 8960, while the sum is 33.

The square root of 20857218 is about 4566.9703305364. The cubic root of 20857218 is about 275.2657178240.

The spelling of 20857218 in words is "twenty million, eight hundred fifty-seven thousand, two hundred eighteen".