20871812 has 12 divisors (see below), whose sum is σ = 39335436. Its totient is φ = 9633120.

The previous prime is 20871769. The next prime is 20871853. The reversal of 20871812 is 21817802.

It can be written as a sum of positive squares in 2 ways, for example, as 5692996 + 15178816 = 2386^2 + 3896^2 .

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 3 ways as a sum of consecutive naturals, for example, 200639 + ... + 200742.

It is an arithmetic number, because the mean of its divisors is an integer number (3277953).

Almost surely, 2^20871812 is an apocalyptic number.

It is an amenable number.

20871812 is a deficient number, since it is larger than the sum of its proper divisors (18463624).

20871812 is a wasteful number, since it uses less digits than its factorization.

20871812 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 401398 (or 401396 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 29.

The square root of 20871812 is about 4568.5678281054. The cubic root of 20871812 is about 275.3299048964.

The spelling of 20871812 in words is "twenty million, eight hundred seventy-one thousand, eight hundred twelve".