21344388 has 48 divisors (see below), whose sum is σ = 54538176. Its totient is φ = 6456960.

The previous prime is 21344369. The next prime is 21344417. The reversal of 21344388 is 88344312.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8395 + ... + 10637.

It is an arithmetic number, because the mean of its divisors is an integer number (1136212).

Almost surely, 2^21344388 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 21344388, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27269088).

21344388 is an abundant number, since it is smaller than the sum of its proper divisors (33193788).

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

21344388 is a wasteful number, since it uses less digits than its factorization.

21344388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2324 (or 2322 counting only the distinct ones).

The product of its digits is 18432, while the sum is 33.

The square root of 21344388 is about 4619.9987012985. The cubic root of 21344388 is about 277.3924069540.

It can be divided in two parts, 213443 and 88, that added together give a triangular number (213531 = T₆₅₃).

The spelling of 21344388 in words is "twenty-one million, three hundred forty-four thousand, three hundred eighty-eight".