1221000021211 has 4 divisors (see below), whose sum is σ = 1222150823424. Its totient is φ = 1219849219000.

The previous prime is 1221000021181. The next prime is 1221000021239. The reversal of 1221000021211 is 1121200001221.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1221000021211 - 2⁷ = 1221000021083 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221000021191 and 1221000021200.

It is not an unprimeable number, because it can be changed into a prime (1221000021011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 575399515 + ... + 575401636.

It is an arithmetic number, because the mean of its divisors is an integer number (305537705856).

Almost surely, 2^{1221000021211} is an apocalyptic number.

1221000021211 is a deficient number, since it is larger than the sum of its proper divisors (1150802213).

1221000021211 is a wasteful number, since it uses less digits than its factorization.

1221000021211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1150802212.

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

Adding to 1221000021211 its reverse (1121200001221), we get a palindrome (2342200022432).

The spelling of 1221000021211 in words is "one trillion, two hundred twenty-one billion, twenty-one thousand, two hundred eleven".