21118530 has 32 divisors (see below), whose sum is σ = 50871744. Its totient is φ = 5610816.

The previous prime is 21118529. The next prime is 21118553. The reversal of 21118530 is 3581112.

It is a junction number, because it is equal to n+sod(n) for n = 21118497 and 21118506.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8064 + ... + 10356.

It is an arithmetic number, because the mean of its divisors is an integer number (1589742).

Almost surely, 2^21118530 is an apocalyptic number.

21118530 is an abundant number, since it is smaller than the sum of its proper divisors (29753214).

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

21118530 is a wasteful number, since it uses less digits than its factorization.

21118530 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2610.

The product of its (nonzero) digits is 240, while the sum is 21.

The square root of 21118530 is about 4595.4901806010. The cubic root of 21118530 is about 276.4105159695.

Adding to 21118530 its reverse (3581112), we get a palindrome (24699642).

The spelling of 21118530 in words is "twenty-one million, one hundred eighteen thousand, five hundred thirty".