20646686 has 16 divisors (see below), whose sum is σ = 32431104. Its totient is φ = 9839544.

The previous prime is 20646667. The next prime is 20646707. The reversal of 20646686 is 68664602.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16271 + ... + 17493.

It is an arithmetic number, because the mean of its divisors is an integer number (2026944).

Almost surely, 2^20646686 is an apocalyptic number.

20646686 is a deficient number, since it is larger than the sum of its proper divisors (11784418).

20646686 is a wasteful number, since it uses less digits than its factorization.

20646686 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1615.

The product of its (nonzero) digits is 82944, while the sum is 38.

The square root of 20646686 is about 4543.8624539042. The cubic root of 20646686 is about 274.3364099261.

The spelling of 20646686 in words is "twenty million, six hundred forty-six thousand, six hundred eighty-six".