21213100000 has 72 divisors (see below), whose sum is σ = 52201018296. Its totient is φ = 8485200000.

The previous prime is 21213099967. The next prime is 21213100043. The reversal of 21213100000 is 131212.

It is a super-2 number, since 2×21213100000² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a self number, because there is not a number n which added to its sum of digits gives 21213100000.

It is a congruent number.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 6066 + ... + 206065.

It is an arithmetic number, because the mean of its divisors is an integer number (725014143).

Almost surely, 2^21213100000 is an apocalyptic number.

21213100000 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 21213100000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26100509148).

21213100000 is an abundant number, since it is smaller than the sum of its proper divisors (30987918296).

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

21213100000 is an frugal number, since it uses more digits than its factorization.

21213100000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 212166 (or 212138 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 10.

Adding to 21213100000 its reverse (131212), we get a palindrome (21213231212).

The spelling of 21213100000 in words is "twenty-one billion, two hundred thirteen million, one hundred thousand".