21031000000 has 98 divisors (see below), whose sum is σ = 52168550984. Its totient is φ = 8412000000.

The previous prime is 21030999971. The next prime is 21031000009. The reversal of 21031000000 is 13012.

It is a super-2 number, since 2×21031000000² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21031000009) 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 13 ways as a sum of consecutive naturals, for example, 989485 + ... + 1010515.

Almost surely, 2^21031000000 is an apocalyptic number.

21031000000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21031000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26084275492).

21031000000 is an abundant number, since it is smaller than the sum of its proper divisors (31137550984).

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

21031000000 is an frugal number, since it uses more digits than its factorization.

21031000000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21073 (or 21038 counting only the distinct ones).

The product of its (nonzero) digits is 6, while the sum is 7.

Adding to 21031000000 its reverse (13012), we get a palindrome (21031013012).

The spelling of 21031000000 in words is "twenty-one billion, thirty-one million", and thus it is an aban number and an uban number.