21893844 has 48 divisors (see below), whose sum is σ = 59222016. Its totient is φ = 6165600.

The previous prime is 21893831. The next prime is 21893887. The reversal of 21893844 is 44839812.

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 a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4129 + ... + 7799.

It is an arithmetic number, because the mean of its divisors is an integer number (1233792).

Almost surely, 2^21893844 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21893844, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29611008).

21893844 is an abundant number, since it is smaller than the sum of its proper divisors (37328172).

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

21893844 is a wasteful number, since it uses less digits than its factorization.

21893844 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3756 (or 3754 counting only the distinct ones).

The product of its digits is 55296, while the sum is 39.

The square root of 21893844 is about 4679.0858081467. The cubic root of 21893844 is about 279.7525194217.

The spelling of 21893844 in words is "twenty-one million, eight hundred ninety-three thousand, eight hundred forty-four".