21443412 has 48 divisors (see below), whose sum is σ = 53000640. Its totient is φ = 6736128.

The previous prime is 21443363. The next prime is 21443431. The reversal of 21443412 is 21434412.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

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, 14248 + ... + 15680.

It is an arithmetic number, because the mean of its divisors is an integer number (1104180).

Almost surely, 2^21443412 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 21443412, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26500320).

21443412 is an abundant number, since it is smaller than the sum of its proper divisors (31557228).

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

21443412 is a wasteful number, since it uses less digits than its factorization.

21443412 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1512 (or 1510 counting only the distinct ones).

The product of its digits is 768, while the sum is 21.

The square root of 21443412 is about 4630.7031863422. The cubic root of 21443412 is about 277.8207183868.

Adding to 21443412 its reverse (21434412), we get a palindrome (42877824).

The spelling of 21443412 in words is "twenty-one million, four hundred forty-three thousand, four hundred twelve".