21012020012021 has 2 divisors, whose sum is σ = 21012020012022. Its totient is φ = 21012020012020.

The previous prime is 21012020011987. The next prime is 21012020012029. The reversal of 21012020012021 is 12021002021012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20999214600100 + 12805411921 = 4582490^2 + 113161^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21012020012021 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21012020011987 and 21012020012005.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21012020012029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10506010006010 + 10506010006011.

It is an arithmetic number, because the mean of its divisors is an integer number (10506010006011).

Almost surely, 2^{21012020012021} is an apocalyptic number.

It is an amenable number.

21012020012021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21012020012021 is an equidigital number, since it uses as much as digits as its factorization.

21012020012021 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 21012020012021 its reverse (12021002021012), we get a palindrome (33033022033033).

The spelling of 21012020012021 in words is "twenty-one trillion, twelve billion, twenty million, twelve thousand, twenty-one".