21208884 has 12 divisors (see below), whose sum is σ = 49487424. Its totient is φ = 7069624.

The previous prime is 21208879. The next prime is 21208903. The reversal of 21208884 is 48880212.

It is a tau number, because it is divible by the number of its divisors (12).

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 3 ways as a sum of consecutive naturals, for example, 883692 + ... + 883715.

It is an arithmetic number, because the mean of its divisors is an integer number (4123952).

Almost surely, 2^21208884 is an apocalyptic number.

It is an amenable number.

21208884 is an abundant number, since it is smaller than the sum of its proper divisors (28278540).

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

21208884 is a wasteful number, since it uses less digits than its factorization.

21208884 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1767414 (or 1767412 counting only the distinct ones).

The product of its (nonzero) digits is 8192, while the sum is 33.

The square root of 21208884 is about 4605.3104129906. The cubic root of 21208884 is about 276.8041554668.

The spelling of 21208884 in words is "twenty-one million, two hundred eight thousand, eight hundred eighty-four".