21115115530 has 16 divisors (see below), whose sum is σ = 40007587680. Its totient is φ = 8001517392.

The previous prime is 21115115509. The next prime is 21115115531. The reversal of 21115115530 is 3551151112.

It is a junction number, because it is equal to n+sod(n) for n = 21115115495 and 21115115504.

It is not an unprimeable number, because it can be changed into a prime (21115115531) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 55565904 + ... + 55566283.

It is an arithmetic number, because the mean of its divisors is an integer number (2500474230).

Almost surely, 2^21115115530 is an apocalyptic number.

21115115530 is a deficient number, since it is larger than the sum of its proper divisors (18892472150).

21115115530 is a wasteful number, since it uses less digits than its factorization.

21115115530 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111132213.

The product of its (nonzero) digits is 750, while the sum is 25.

Adding to 21115115530 its reverse (3551151112), we get a palindrome (24666266642).

The spelling of 21115115530 in words is "twenty-one billion, one hundred fifteen million, one hundred fifteen thousand, five hundred thirty".