20857856 has 22 divisors (see below), whose sum is σ = 41697390. Its totient is φ = 10428416.

The previous prime is 20857843. The next prime is 20857867. The reversal of 20857856 is 65875802.

It can be written as a sum of positive squares in only one way, i.e., 19219456 + 1638400 = 4384^2 + 1280^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9161 + ... + 11208.

Almost surely, 2^20857856 is an apocalyptic number.

It is an amenable number.

20857856 is a deficient number, since it is larger than the sum of its proper divisors (20839534).

20857856 is an equidigital number, since it uses as much as digits as its factorization.

20857856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20389 (or 20371 counting only the distinct ones).

The product of its (nonzero) digits is 134400, while the sum is 41.

The square root of 20857856 is about 4567.0401793722. The cubic root of 20857856 is about 275.2685244901.

The spelling of 20857856 in words is "twenty million, eight hundred fifty-seven thousand, eight hundred fifty-six".