21130320042 has 64 divisors (see below), whose sum is σ = 50770177920. Its totient is φ = 6475680000.

The previous prime is 21130320007. The next prime is 21130320061. The reversal of 21130320042 is 24002303112.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21130319997 and 21130320024.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 116242 + ... + 236162.

It is an arithmetic number, because the mean of its divisors is an integer number (793284030).

Almost surely, 2^21130320042 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21130320042, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25385088960).

21130320042 is an abundant number, since it is smaller than the sum of its proper divisors (29639857878).

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

21130320042 is a wasteful number, since it uses less digits than its factorization.

21130320042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 120196 (or 120190 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

Adding to 21130320042 its reverse (24002303112), we get a palindrome (45132623154).

The spelling of 21130320042 in words is "twenty-one billion, one hundred thirty million, three hundred twenty thousand, forty-two".