21876424 has 8 divisors (see below), whose sum is σ = 41018310. Its totient is φ = 10938208.

The previous prime is 21876419. The next prime is 21876451. The reversal of 21876424 is 42467812.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 20412324 + 1464100 = 4518^2 + 1210^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a self number, because there is not a number n which added to its sum of digits gives 21876424.

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 as a sum of consecutive naturals, namely, 1367269 + ... + 1367284.

Almost surely, 2^21876424 is an apocalyptic number.

It is an amenable number.

21876424 is a deficient number, since it is larger than the sum of its proper divisors (19141886).

21876424 is a wasteful number, since it uses less digits than its factorization.

21876424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2734559 (or 2734555 counting only the distinct ones).

The product of its digits is 21504, while the sum is 34.

The square root of 21876424 is about 4677.2239629934. The cubic root of 21876424 is about 279.6783040098.

The spelling of 21876424 in words is "twenty-one million, eight hundred seventy-six thousand, four hundred twenty-four".