21876388 has 12 divisors (see below), whose sum is σ = 38319820. Its totient is φ = 10927872.

The previous prime is 21876377. The next prime is 21876389. The reversal of 21876388 is 88367812.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 2849344 + 19027044 = 1688^2 + 4362^2 .

It is a hoax number, since the sum of its digits (43) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (21876389) by changing a digit.

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, 4120 + ... + 7792.

Almost surely, 2^21876388 is an apocalyptic number.

It is an amenable number.

21876388 is a deficient number, since it is larger than the sum of its proper divisors (16443432).

21876388 is a wasteful number, since it uses less digits than its factorization.

21876388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5166 (or 5164 counting only the distinct ones).

The product of its digits is 129024, while the sum is 43.

The square root of 21876388 is about 4677.2201145552. The cubic root of 21876388 is about 279.6781505962.

The spelling of 21876388 in words is "twenty-one million, eight hundred seventy-six thousand, three hundred eighty-eight".