1211012001221 has 4 divisors (see below), whose sum is σ = 1321104001344. Its totient is φ = 1100920001100.

The previous prime is 1211012001217. The next prime is 1211012001223. The reversal of 1211012001221 is 1221002101121.

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 1211012001221 - 2² = 1211012001217 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1211012001196 and 1211012001205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211012001223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 55046000045 + ... + 55046000066.

It is an arithmetic number, because the mean of its divisors is an integer number (330276000336).

Almost surely, 2^{1211012001221} is an apocalyptic number.

1211012001221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1211012001221 is a deficient number, since it is larger than the sum of its proper divisors (110092000123).

1211012001221 is a wasteful number, since it uses less digits than its factorization.

1211012001221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110092000122.

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

Adding to 1211012001221 its reverse (1221002101121), we get a palindrome (2432014102342).

The spelling of 1211012001221 in words is "one trillion, two hundred eleven billion, twelve million, one thousand, two hundred twenty-one".