21384252 has 36 divisors (see below), whose sum is σ = 55921320. Its totient is φ = 6881952.

The previous prime is 21384241. The next prime is 21384257. The reversal of 21384252 is 25248312.

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21384257) 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 11 ways as a sum of consecutive naturals, for example, 9198 + ... + 11285.

It is an arithmetic number, because the mean of its divisors is an integer number (1553370).

Almost surely, 2^21384252 is an apocalyptic number.

It is an amenable number.

21384252 is an abundant number, since it is smaller than the sum of its proper divisors (34537068).

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

21384252 is a wasteful number, since it uses less digits than its factorization.

21384252 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20522 (or 20517 counting only the distinct ones).

The product of its digits is 3840, while the sum is 27.

The square root of 21384252 is about 4624.3109757022. The cubic root of 21384252 is about 277.5649908650.

The spelling of 21384252 in words is "twenty-one million, three hundred eighty-four thousand, two hundred fifty-two".