21398304 has 48 divisors (see below), whose sum is σ = 56615328. Its totient is φ = 7076352.

The previous prime is 21398287. The next prime is 21398327. The reversal of 21398304 is 40389312.

It is a tau number, because it is divible by the number of its divisors (48).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12339 + ... + 13965.

It is an arithmetic number, because the mean of its divisors is an integer number (1179486).

Almost surely, 2^21398304 is an apocalyptic number.

21398304 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21398304, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28307664).

21398304 is an abundant number, since it is smaller than the sum of its proper divisors (35217024).

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

21398304 is a wasteful number, since it uses less digits than its factorization.

21398304 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1777 (or 1769 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 30.

The square root of 21398304 is about 4625.8300876708. The cubic root of 21398304 is about 277.6257753032.

The spelling of 21398304 in words is "twenty-one million, three hundred ninety-eight thousand, three hundred four".