20856866 has 8 divisors (see below), whose sum is σ = 31311360. Its totient is φ = 10419748.

The previous prime is 20856839. The next prime is 20856877. The reversal of 20856866 is 66865802.

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 746 + ... + 6501.

It is an arithmetic number, because the mean of its divisors is an integer number (3913920).

Almost surely, 2^20856866 is an apocalyptic number.

20856866 is a deficient number, since it is larger than the sum of its proper divisors (10454494).

20856866 is a wasteful number, since it uses less digits than its factorization.

20856866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8688.

The product of its (nonzero) digits is 138240, while the sum is 41.

The square root of 20856866 is about 4566.9317927904. The cubic root of 20856866 is about 275.2641692941.

The spelling of 20856866 in words is "twenty million, eight hundred fifty-six thousand, eight hundred sixty-six".