21001000001200 has 60 divisors (see below), whose sum is σ = 51062792975208. Its totient is φ = 8299190348800.

The previous prime is 21001000001197. The next prime is 21001000001209. The reversal of 21001000001200 is 210000010012.

It is not an unprimeable number, because it can be changed into a prime (21001000001209) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 316246921 + ... + 316313320.

Almost surely, 2^{21001000001200} is an apocalyptic number.

21001000001200 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21001000001200 is an abundant number, since it is smaller than the sum of its proper divisors (30061792974008).

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

21001000001200 is a wasteful number, since it uses less digits than its factorization.

21001000001200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 632560342 (or 632560331 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 7.

Adding to 21001000001200 its reverse (210000010012), we get a palindrome (21211000011212).

The spelling of 21001000001200 in words is "twenty-one trillion, one billion, one thousand, two hundred".