21031231120 has 20 divisors (see below), whose sum is σ = 48897612540. Its totient is φ = 8412492416.

The previous prime is 21031231099. The next prime is 21031231121. The reversal of 21031231120 is 2113213012.

It can be written as a sum of positive squares in 2 ways, for example, as 8903054736 + 12128176384 = 94356^2 + 110128^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a junction number, because it is equal to n+sod(n) for n = 21031231094 and 21031231103.

It is not an unprimeable number, because it can be changed into a prime (21031231121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 131445115 + ... + 131445274.

It is an arithmetic number, because the mean of its divisors is an integer number (2444880627).

Almost surely, 2^21031231120 is an apocalyptic number.

21031231120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21031231120 is an abundant number, since it is smaller than the sum of its proper divisors (27866381420).

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

21031231120 is a wasteful number, since it uses less digits than its factorization.

21031231120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 262890402 (or 262890396 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 16.

Adding to 21031231120 its reverse (2113213012), we get a palindrome (23144444132).

The spelling of 21031231120 in words is "twenty-one billion, thirty-one million, two hundred thirty-one thousand, one hundred twenty".