1211200120021 has 4 divisors (see below), whose sum is σ = 1211561999712. Its totient is φ = 1210838240332.

The previous prime is 1211200120001. The next prime is 1211200120061. The reversal of 1211200120021 is 1200210021121.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1211200120021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1211200119983 and 1211200120010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211200120001) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 180934825 + ... + 180941518.

It is an arithmetic number, because the mean of its divisors is an integer number (302890499928).

Almost surely, 2^{1211200120021} is an apocalyptic number.

It is an amenable number.

1211200120021 is a deficient number, since it is larger than the sum of its proper divisors (361879691).

1211200120021 is an equidigital number, since it uses as much as digits as its factorization.

1211200120021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 361879690.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 1211200120021 its reverse (1200210021121), we get a palindrome (2411410141142).

The spelling of 1211200120021 in words is "one trillion, two hundred eleven billion, two hundred million, one hundred twenty thousand, twenty-one".