1020200000021 has 2 divisors, whose sum is σ = 1020200000022. Its totient is φ = 1020200000020.

The previous prime is 1020200000011. The next prime is 1020200000047. The reversal of 1020200000021 is 1200000020201.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 705238846225 + 314961153796 = 839785^2 + 561214^2 .

It is a cyclic number.

It is not a de Polignac number, because 1020200000021 - 2¹⁸ = 1020199737877 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1020199999954 and 1020200000008.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1020200000011) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 510100000010 + 510100000011.

It is an arithmetic number, because the mean of its divisors is an integer number (510100000011).

Almost surely, 2^{1020200000021} is an apocalyptic number.

It is an amenable number.

1020200000021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1020200000021 is an equidigital number, since it uses as much as digits as its factorization.

1020200000021 is an evil number, because the sum of its binary digits is even.

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

Adding to 1020200000021 its reverse (1200000020201), we get a palindrome (2220200020222).

The spelling of 1020200000021 in words is "one trillion, twenty billion, two hundred million, twenty-one", and thus it is an aban number.