21381304 has 32 divisors (see below), whose sum is σ = 46080000. Its totient is φ = 9110880.

The previous prime is 21381281. The next prime is 21381307. The reversal of 21381304 is 40318312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21381307) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9697 + ... + 11695.

It is an arithmetic number, because the mean of its divisors is an integer number (1440000).

Almost surely, 2^21381304 is an apocalyptic number.

It is an amenable number.

21381304 is an abundant number, since it is smaller than the sum of its proper divisors (24698696).

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

21381304 is a wasteful number, since it uses less digits than its factorization.

21381304 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2203 (or 2199 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 21381304 is about 4623.9922145263. The cubic root of 21381304 is about 277.5522353850.

Adding to 21381304 its reverse (40318312), we get a palindrome (61699616).

The spelling of 21381304 in words is "twenty-one million, three hundred eighty-one thousand, three hundred four".