21012011200 has 168 divisors, whose sum is σ = 52777028304. Its totient is φ = 8231424000.

The previous prime is 21012011191. The next prime is 21012011221. The reversal of 21012011200 is 211021012.

It is a super-2 number, since 2×21012011200² (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 an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 44993367 + ... + 44993833.

It is an arithmetic number, because the mean of its divisors is an integer number (314148978).

Almost surely, 2^21012011200 is an apocalyptic number.

21012011200 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 21012011200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26388514152).

21012011200 is an abundant number, since it is smaller than the sum of its proper divisors (31765017104).

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

21012011200 is a wasteful number, since it uses less digits than its factorization.

21012011200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1011 (or 996 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 21012011200 its reverse (211021012), we get a palindrome (21223032212).

The spelling of 21012011200 in words is "twenty-one billion, twelve million, eleven thousand, two hundred".