21384036 has 72 divisors (see below), whose sum is σ = 56026880. Its totient is φ = 6873984.

The previous prime is 21383969. The next prime is 21384061. The reversal of 21384036 is 63048312.

It is a happy number.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 207561 + ... + 207663.

Almost surely, 2^21384036 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 21384036, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28013440).

21384036 is an abundant number, since it is smaller than the sum of its proper divisors (34642844).

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

21384036 is a wasteful number, since it uses less digits than its factorization.

21384036 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 265 (or 260 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

The square root of 21384036 is about 4624.2876208125. The cubic root of 21384036 is about 277.5640563106.

The spelling of 21384036 in words is "twenty-one million, three hundred eighty-four thousand, thirty-six".