21230320 has 40 divisors (see below), whose sum is σ = 51068160. Its totient is φ = 8198400.

The previous prime is 21230309. The next prime is 21230329. The reversal of 21230320 is 2303212.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (40).

It is a self number, because there is not a number n which added to its sum of digits gives 21230320.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21230329) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2256 + ... + 6895.

It is an arithmetic number, because the mean of its divisors is an integer number (1276704).

Almost surely, 2^21230320 is an apocalyptic number.

21230320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21230320 is an abundant number, since it is smaller than the sum of its proper divisors (29837840).

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

21230320 is a wasteful number, since it uses less digits than its factorization.

21230320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9193 (or 9187 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 13.

The square root of 21230320 is about 4607.6371384908. The cubic root of 21230320 is about 276.8973801733.

Adding to 21230320 its reverse (2303212), we get a palindrome (23533532).

The spelling of 21230320 in words is "twenty-one million, two hundred thirty thousand, three hundred twenty".