1211000020021 has 16 divisors (see below), whose sum is σ = 1407376535040. Its totient is φ = 1030400647920.

The previous prime is 1211000020007. The next prime is 1211000020057. The reversal of 1211000020021 is 1200200001121.

It is a cyclic number.

It is not a de Polignac number, because 1211000020021 - 2⁵ = 1211000019989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211000020091) 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 15 ways as a sum of consecutive naturals, for example, 34887825 + ... + 34922518.

It is an arithmetic number, because the mean of its divisors is an integer number (87961033440).

Almost surely, 2^{1211000020021} is an apocalyptic number.

1211000020021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1211000020021 is a deficient number, since it is larger than the sum of its proper divisors (196376515019).

1211000020021 is a wasteful number, since it uses less digits than its factorization.

1211000020021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69810456.

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 1211000020021 its reverse (1200200001121), we get a palindrome (2411200021142).

The spelling of 1211000020021 in words is "one trillion, two hundred eleven billion, twenty thousand, twenty-one".