21689884 has 12 divisors (see below), whose sum is σ = 37999584. Its totient is φ = 10832864.

The previous prime is 21689867. The next prime is 21689893. The reversal of 21689884 is 48898612.

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, 1917 + ... + 6859.

It is an arithmetic number, because the mean of its divisors is an integer number (3166632).

Almost surely, 2^21689884 is an apocalyptic number.

It is an amenable number.

21689884 is a deficient number, since it is larger than the sum of its proper divisors (16309700).

21689884 is a wasteful number, since it uses less digits than its factorization.

21689884 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6044 (or 6042 counting only the distinct ones).

The product of its digits is 221184, while the sum is 46.

The square root of 21689884 is about 4657.2399551666. The cubic root of 21689884 is about 278.8810959436.

It can be divided in two parts, 216 and 89884, that added together give a triangular number (90100 = T₄₂₄).

The spelling of 21689884 in words is "twenty-one million, six hundred eighty-nine thousand, eight hundred eighty-four".