21200001000 has 512 divisors, whose sum is σ = 71978250240. Its totient is φ = 5184000000.

The previous prime is 21200000981. The next prime is 21200001001. The reversal of 21200001000 is 10000212.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (6).

It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.

It is a self number, because there is not a number n which added to its sum of digits gives 21200001000.

It is not an unprimeable number, because it can be changed into a prime (21200001001) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 209900950 + ... + 209901050.

It is an arithmetic number, because the mean of its divisors is an integer number (140582520).

Almost surely, 2^21200001000 is an apocalyptic number.

21200001000 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 21200001000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35989125120).

21200001000 is an abundant number, since it is smaller than the sum of its proper divisors (50778249240).

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

21200001000 is a wasteful number, since it uses less digits than its factorization.

21200001000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 254 (or 240 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 6.

Adding to 21200001000 its reverse (10000212), we get a palindrome (21210001212).

The spelling of 21200001000 in words is "twenty-one billion, two hundred million, one thousand".