1211212220021 has 16 divisors (see below), whose sum is σ = 1243019832384. Its totient is φ = 1179572575104.

The previous prime is 1211212219981. The next prime is 1211212220027. The reversal of 1211212220021 is 1200222121121.

It is a cyclic number.

It is not a de Polignac number, because 1211212220021 - 2²² = 1211208025717 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 (1211212220027) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 44934470 + ... + 44961416.

It is an arithmetic number, because the mean of its divisors is an integer number (77688739524).

Almost surely, 2^{1211212220021} is an apocalyptic number.

It is an amenable number.

1211212220021 is a deficient number, since it is larger than the sum of its proper divisors (31807612363).

1211212220021 is a wasteful number, since it uses less digits than its factorization.

1211212220021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30020.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 1211212220021 its reverse (1200222121121), we get a palindrome (2411434341142).

The spelling of 1211212220021 in words is "one trillion, two hundred eleven billion, two hundred twelve million, two hundred twenty thousand, twenty-one".