21121310000 has 200 divisors, whose sum is σ = 61883316000. Its totient is φ = 6815232000.

The previous prime is 21121309987. The next prime is 21121310003. The reversal of 21121310000 is 1312112.

It is a tau number, because it is divible by the number of its divisors (200).

It is a super-2 number, since 2×21121310000² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21121310003) by changing a digit.

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 39 ways as a sum of consecutive naturals, for example, 1181126 + ... + 1198874.

It is an arithmetic number, because the mean of its divisors is an integer number (309416580).

Almost surely, 2^21121310000 is an apocalyptic number.

21121310000 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 21121310000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30941658000).

21121310000 is an abundant number, since it is smaller than the sum of its proper divisors (40762006000).

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

21121310000 is a wasteful number, since it uses less digits than its factorization.

21121310000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17801 (or 17780 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 11.

Adding to 21121310000 its reverse (1312112), we get a palindrome (21122622112).

The spelling of 21121310000 in words is "twenty-one billion, one hundred twenty-one million, three hundred ten thousand".