1211001002021 has 4 divisors (see below), whose sum is σ = 1211426963712. Its totient is φ = 1210575040332.

The previous prime is 1211001001993. The next prime is 1211001002033. The reversal of 1211001002021 is 1202001001121.

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 1211001002021 - 2¹⁸ = 1211000739877 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1211001001993 and 1211001002011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211001002621) 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, 212976581 + ... + 212982266.

It is an arithmetic number, because the mean of its divisors is an integer number (302856740928).

Almost surely, 2^{1211001002021} is an apocalyptic number.

It is an amenable number.

1211001002021 is a deficient number, since it is larger than the sum of its proper divisors (425961691).

1211001002021 is an equidigital number, since it uses as much as digits as its factorization.

1211001002021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 425961690.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 1211001002021 its reverse (1202001001121), we get a palindrome (2413002003142).

The spelling of 1211001002021 in words is "one trillion, two hundred eleven billion, one million, two thousand, twenty-one".