21001201200 has 360 divisors, whose sum is σ = 83474428128. Its totient is φ = 4789739520.

The previous prime is 21001201159. The next prime is 21001201231. The reversal of 21001201200 is 210210012.

It is a tau number, because it is divible by the number of its divisors (360).

It is a Harshad number since it is a multiple of its sum of digits (9).

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

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 21495112 + ... + 21496088.

Almost surely, 2^21001201200 is an apocalyptic number.

21001201200 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 21001201200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41737214064).

21001201200 is an abundant number, since it is smaller than the sum of its proper divisors (62473226928).

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

21001201200 is a wasteful number, since it uses less digits than its factorization.

21001201200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1861 (or 1847 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 21001201200 its reverse (210210012), we get a palindrome (21211411212).

The spelling of 21001201200 in words is "twenty-one billion, one million, two hundred one thousand, two hundred".