21031321120 has 24 divisors (see below), whose sum is σ = 49686496524. Its totient is φ = 8412528384.

The previous prime is 21031321093. The next prime is 21031321127. The reversal of 21031321120 is 2112313012.

It can be written as a sum of positive squares in 2 ways, for example, as 19509384976 + 1521936144 = 139676^2 + 39012^2 .

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 = 21031321094 and 21031321103.

It is not an unprimeable number, because it can be changed into a prime (21031321127) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 65722719 + ... + 65723038.

Almost surely, 2^21031321120 is an apocalyptic number.

21031321120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21031321120 is an abundant number, since it is smaller than the sum of its proper divisors (28655175404).

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

21031321120 is a wasteful number, since it uses less digits than its factorization.

21031321120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131445772 (or 131445764 counting only the distinct ones).

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

Adding to 21031321120 its reverse (2112313012), we get a palindrome (23143634132).

The spelling of 21031321120 in words is "twenty-one billion, thirty-one million, three hundred twenty-one thousand, one hundred twenty".