21112155530 has 16 divisors (see below), whose sum is σ = 38522454984. Its totient is φ = 8329178880.

The previous prime is 21112155511. The next prime is 21112155541. The reversal of 21112155530 is 3555121112.

It can be written as a sum of positive squares in 4 ways, for example, as 10638065881 + 10474089649 = 103141^2 + 102343^2 .

It is a super-2 number, since 2×21112155530² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21112155530.

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, 14459651 + ... + 14461110.

Almost surely, 2^21112155530 is an apocalyptic number.

21112155530 is a deficient number, since it is larger than the sum of its proper divisors (17410299454).

21112155530 is a wasteful number, since it uses less digits than its factorization.

21112155530 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28920841.

The product of its (nonzero) digits is 1500, while the sum is 26.

Adding to 21112155530 its reverse (3555121112), we get a palindrome (24667276642).

The spelling of 21112155530 in words is "twenty-one billion, one hundred twelve million, one hundred fifty-five thousand, five hundred thirty".