21343872 has 128 divisors (see below), whose sum is σ = 64235520. Its totient is φ = 6220800.

The previous prime is 21343853. The next prime is 21343901. The reversal of 21343872 is 27834312.

It is a tau number, because it is divible by the number of its divisors (128).

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, 130863 + ... + 131025.

It is an arithmetic number, because the mean of its divisors is an integer number (501840).

Almost surely, 2^21343872 is an apocalyptic number.

21343872 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21343872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32117760).

21343872 is an abundant number, since it is smaller than the sum of its proper divisors (42891648).

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

21343872 is a wasteful number, since it uses less digits than its factorization.

21343872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 222 (or 210 counting only the distinct ones).

The product of its digits is 8064, while the sum is 30.

The square root of 21343872 is about 4619.9428567895. The cubic root of 21343872 is about 277.3901716180.

It can be divided in two parts, 2134 and 3872, that added together give a palindrome (6006).

The spelling of 21343872 in words is "twenty-one million, three hundred forty-three thousand, eight hundred seventy-two".