21130443242 has 4 divisors (see below), whose sum is σ = 31695664866. Its totient is φ = 10565221620.

The previous prime is 21130443239. The next prime is 21130443247. The reversal of 21130443242 is 24234403112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 16811456281 + 4318986961 = 129659^2 + 65719^2 .

It is not an unprimeable number, because it can be changed into a prime (21130443247) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5282610809 + ... + 5282610812.

Almost surely, 2^21130443242 is an apocalyptic number.

21130443242 is a deficient number, since it is larger than the sum of its proper divisors (10565221624).

21130443242 is a wasteful number, since it uses less digits than its factorization.

21130443242 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10565221623.

The product of its (nonzero) digits is 4608, while the sum is 26.

Adding to 21130443242 its reverse (24234403112), we get a palindrome (45364846354).

The spelling of 21130443242 in words is "twenty-one billion, one hundred thirty million, four hundred forty-three thousand, two hundred forty-two".