21234320 has 40 divisors (see below), whose sum is σ = 49564536. Its totient is φ = 8460288.

The previous prime is 21234307. The next prime is 21234347. The reversal of 21234320 is 2343212.

It can be written as a sum of positive squares in 4 ways, for example, as 1449616 + 19784704 = 1204^2 + 4448^2 .

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

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, 34334 + ... + 34946.

Almost surely, 2^21234320 is an apocalyptic number.

21234320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21234320 is an abundant number, since it is smaller than the sum of its proper divisors (28330216).

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

21234320 is a wasteful number, since it uses less digits than its factorization.

21234320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1059 (or 1053 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 17.

The square root of 21234320 is about 4608.0711800058. The cubic root of 21234320 is about 276.9147691398.

Adding to 21234320 its reverse (2343212), we get a palindrome (23577532).

The spelling of 21234320 in words is "twenty-one million, two hundred thirty-four thousand, three hundred twenty".