21384308 has 24 divisors (see below), whose sum is σ = 41023584. Its totient is φ = 9672800.

The previous prime is 21384301. The next prime is 21384313. The reversal of 21384308 is 80348312.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21384301) 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, 8918 + ... + 11058.

It is an arithmetic number, because the mean of its divisors is an integer number (1709316).

Almost surely, 2^21384308 is an apocalyptic number.

It is an amenable number.

21384308 is a deficient number, since it is larger than the sum of its proper divisors (19639276).

21384308 is a wasteful number, since it uses less digits than its factorization.

21384308 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2383 (or 2381 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 29.

The square root of 21384308 is about 4624.3170306544. The cubic root of 21384308 is about 277.5652331559.

It can be divided in two parts, 2138 and 4308, that added together give a palindrome (6446).

The spelling of 21384308 in words is "twenty-one million, three hundred eighty-four thousand, three hundred eight".