20820866 has 24 divisors (see below), whose sum is σ = 34983792. Its totient is φ = 9216800.

The previous prime is 20820851. The next prime is 20820881. The reversal of 20820866 is 66802802.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (20820851) and next prime (20820881).

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 11 ways as a sum of consecutive naturals, for example, 36701 + ... + 37263.

It is an arithmetic number, because the mean of its divisors is an integer number (1457658).

Almost surely, 2^20820866 is an apocalyptic number.

20820866 is a deficient number, since it is larger than the sum of its proper divisors (14162926).

20820866 is a wasteful number, since it uses less digits than its factorization.

20820866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 658 (or 617 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 32.

The square root of 20820866 is about 4562.9887135517. The cubic root of 20820866 is about 275.1057048184.

The spelling of 20820866 in words is "twenty million, eight hundred twenty thousand, eight hundred sixty-six".