21871884 has 24 divisors (see below), whose sum is σ = 52414768. Its totient is φ = 7093440.

The previous prime is 21871849. The next prime is 21871903. The reversal of 21871884 is 48817812.

It is a happy number.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors.

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 7 ways as a sum of consecutive naturals, for example, 24187 + ... + 25074.

Almost surely, 2^21871884 is an apocalyptic number.

It is an amenable number.

21871884 is an abundant number, since it is smaller than the sum of its proper divisors (30542884).

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

21871884 is a wasteful number, since it uses less digits than its factorization.

21871884 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49305 (or 49303 counting only the distinct ones).

The product of its digits is 28672, while the sum is 39.

The square root of 21871884 is about 4676.7386071920. The cubic root of 21871884 is about 279.6589555193.

The spelling of 21871884 in words is "twenty-one million, eight hundred seventy-one thousand, eight hundred eighty-four".