21641304 has 32 divisors (see below), whose sum is σ = 56952000. Its totient is φ = 6833952.

The previous prime is 21641303. The next prime is 21641309. The reversal of 21641304 is 40314612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21641303) 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, 23274 + ... + 24185.

It is an arithmetic number, because the mean of its divisors is an integer number (1779750).

Almost surely, 2^21641304 is an apocalyptic number.

21641304 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21641304 is an abundant number, since it is smaller than the sum of its proper divisors (35310696).

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

21641304 is a wasteful number, since it uses less digits than its factorization.

21641304 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47487 (or 47483 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 21.

The square root of 21641304 is about 4652.0214960810. The cubic root of 21641304 is about 278.6727319737.

Adding to 21641304 its reverse (40314612), we get a palindrome (61955916).

It can be divided in two parts, 21641 and 304, that added together give a triangular number (21945 = T₂₀₉).

The spelling of 21641304 in words is "twenty-one million, six hundred forty-one thousand, three hundred four".