21530264 has 16 divisors (see below), whose sum is σ = 46136400. Its totient is φ = 9227232.

The previous prime is 21530261. The next prime is 21530281. The reversal of 21530264 is 46203512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21530261) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 192179 + ... + 192290.

It is an arithmetic number, because the mean of its divisors is an integer number (2883525).

Almost surely, 2^21530264 is an apocalyptic number.

It is an amenable number.

21530264 is an abundant number, since it is smaller than the sum of its proper divisors (24606136).

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

21530264 is a wasteful number, since it uses less digits than its factorization.

21530264 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 384482 (or 384478 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 21530264 is about 4640.0715511725. The cubic root of 21530264 is about 278.1952977881.

Adding to 21530264 its reverse (46203512), we get a palindrome (67733776).

The spelling of 21530264 in words is "twenty-one million, five hundred thirty thousand, two hundred sixty-four".