21163530 has 64 divisors (see below), whose sum is σ = 54120960. Its totient is φ = 5281344.

The previous prime is 21163507. The next prime is 21163531. The reversal of 21163530 is 3536112.

It is a junction number, because it is equal to n+sod(n) for n = 21163497 and 21163506.

It is not an unprimeable number, because it can be changed into a prime (21163531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 60817 + ... + 61163.

It is an arithmetic number, because the mean of its divisors is an integer number (845640).

Almost surely, 2^21163530 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21163530, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27060480).

21163530 is an abundant number, since it is smaller than the sum of its proper divisors (32957430).

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

21163530 is a wasteful number, since it uses less digits than its factorization.

21163530 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 483.

The product of its (nonzero) digits is 540, while the sum is 21.

The square root of 21163530 is about 4600.3836796511. The cubic root of 21163530 is about 276.6067046389.

Adding to 21163530 its reverse (3536112), we get a palindrome (24699642).

The spelling of 21163530 in words is "twenty-one million, one hundred sixty-three thousand, five hundred thirty".