1212100220021 has 2 divisors, whose sum is σ = 1212100220022. Its totient is φ = 1212100220020.

The previous prime is 1212100219933. The next prime is 1212100220057. The reversal of 1212100220021 is 1200220012121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1146428469796 + 65671750225 = 1070714^2 + 256265^2 .

It is a cyclic number.

It is not a de Polignac number, because 1212100220021 - 2¹⁴ = 1212100203637 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1212100219978 and 1212100220005.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1212100220081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 606050110010 + 606050110011.

It is an arithmetic number, because the mean of its divisors is an integer number (606050110011).

Almost surely, 2^{1212100220021} is an apocalyptic number.

It is an amenable number.

1212100220021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1212100220021 is an equidigital number, since it uses as much as digits as its factorization.

1212100220021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 1212100220021 its reverse (1200220012121), we get a palindrome (2412320232142).

The spelling of 1212100220021 in words is "one trillion, two hundred twelve billion, one hundred million, two hundred twenty thousand, twenty-one".