21001001200120 has 32 divisors (see below), whose sum is σ = 47253636979920. Its totient is φ = 8400154385920.

The previous prime is 21001001200099. The next prime is 21001001200181. The reversal of 21001001200120 is 2100210010012.

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

It is a junction number, because it is equal to n+sod(n) for n = 21001001200097 and 21001001200106.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6304897 + ... + 9041776.

Almost surely, 2^{21001001200120} is an apocalyptic number.

21001001200120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21001001200120 is an abundant number, since it is smaller than the sum of its proper divisors (26252635779800).

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

21001001200120 is a wasteful number, since it uses less digits than its factorization.

21001001200120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15380895 (or 15380891 counting only the distinct ones).

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

Adding to 21001001200120 its reverse (2100210010012), we get a palindrome (23101211210132).

The spelling of 21001001200120 in words is "twenty-one trillion, one billion, one million, two hundred thousand, one hundred twenty".