20801866 has 16 divisors (see below), whose sum is σ = 31946400. Its totient is φ = 10155568.

The previous prime is 20801849. The next prime is 20801873. The reversal of 20801866 is 66810802.

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, 19905 + ... + 20923.

It is an arithmetic number, because the mean of its divisors is an integer number (1996650).

Almost surely, 2^20801866 is an apocalyptic number.

20801866 is a deficient number, since it is larger than the sum of its proper divisors (11144534).

20801866 is a wasteful number, since it uses less digits than its factorization.

20801866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1253.

The product of its (nonzero) digits is 4608, while the sum is 31.

The square root of 20801866 is about 4560.9062695916. The cubic root of 20801866 is about 275.0219971385.

The spelling of 20801866 in words is "twenty million, eight hundred one thousand, eight hundred sixty-six".