21006336 has 96 divisors (see below), whose sum is σ = 60540480. Its totient is φ = 6438912.

The previous prime is 21006329. The next prime is 21006341. The reversal of 21006336 is 63360012.

It is a tau number, because it is divible by the number of its divisors (96).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 79741 + ... + 80003.

It is an arithmetic number, because the mean of its divisors is an integer number (630630).

Almost surely, 2^21006336 is an apocalyptic number.

21006336 is a gapful number since it is divisible by the number (26) 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 21006336, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30270240).

21006336 is an abundant number, since it is smaller than the sum of its proper divisors (39534144).

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

21006336 is a wasteful number, since it uses less digits than its factorization.

21006336 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 301 (or 281 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 21.

The square root of 21006336 is about 4583.2669570951. The cubic root of 21006336 is about 275.9201617426.

Adding to 21006336 its reverse (63360012), we get a palindrome (84366348).

The spelling of 21006336 in words is "twenty-one million, six thousand, three hundred thirty-six".