1211000212121 has 4 divisors (see below), whose sum is σ = 1384000242432. Its totient is φ = 1038000181812.

The previous prime is 1211000212091. The next prime is 1211000212141. The reversal of 1211000212121 is 1212120001121.

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 not a de Polignac number, because 1211000212121 - 2¹⁸ = 1210999949977 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1211000212096 and 1211000212105.

It is not an unprimeable number, because it can be changed into a prime (1211000212141) 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, 86500015145 + ... + 86500015158.

It is an arithmetic number, because the mean of its divisors is an integer number (346000060608).

Almost surely, 2^{1211000212121} is an apocalyptic number.

It is an amenable number.

1211000212121 is a deficient number, since it is larger than the sum of its proper divisors (173000030311).

1211000212121 is an equidigital number, since it uses as much as digits as its factorization.

1211000212121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 173000030310.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 1211000212121 its reverse (1212120001121), we get a palindrome (2423120213242).

The spelling of 1211000212121 in words is "one trillion, two hundred eleven billion, two hundred twelve thousand, one hundred twenty-one".