21415344 has 40 divisors (see below), whose sum is σ = 56157120. Its totient is φ = 7030848.

The previous prime is 21415321. The next prime is 21415349. The reversal of 21415344 is 44351412.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21415349) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 114 + ... + 6545.

It is an arithmetic number, because the mean of its divisors is an integer number (1403928).

Almost surely, 2^21415344 is an apocalyptic number.

21415344 is a gapful number since it is divisible by the number (24) 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 21415344, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28078560).

21415344 is an abundant number, since it is smaller than the sum of its proper divisors (34741776).

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

21415344 is a wasteful number, since it uses less digits than its factorization.

21415344 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6737 (or 6731 counting only the distinct ones).

The product of its digits is 1920, while the sum is 24.

The square root of 21415344 is about 4627.6715527358. The cubic root of 21415344 is about 277.6994491799.

Adding to 21415344 its reverse (44351412), we get a palindrome (65766756).

The spelling of 21415344 in words is "twenty-one million, four hundred fifteen thousand, three hundred forty-four".