21036808 has 16 divisors (see below), whose sum is σ = 42478380. Its totient is φ = 9709248.

The previous prime is 21036797. The next prime is 21036809. The reversal of 21036808 is 80863012.

It can be written as a sum of positive squares in 2 ways, for example, as 20629764 + 407044 = 4542^2 + 638^2 .

It is not an unprimeable number, because it can be changed into a prime (21036809) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 101035 + ... + 101242.

Almost surely, 2^21036808 is an apocalyptic number.

It is an amenable number.

21036808 is an abundant number, since it is smaller than the sum of its proper divisors (21441572).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21036808 is a wasteful number, since it uses less digits than its factorization.

21036808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 202296 (or 202292 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 28.

The square root of 21036808 is about 4586.5900187394. The cubic root of 21036808 is about 276.0535147929.

It can be divided in two parts, 2103 and 6808, that added together give a triangular number (8911 = T₁₃₃).

The spelling of 21036808 in words is "twenty-one million, thirty-six thousand, eight hundred eight".