1020012100021 has 2 divisors, whose sum is σ = 1020012100022. Its totient is φ = 1020012100020.

The previous prime is 1020012100007. The next prime is 1020012100031. The reversal of 1020012100021 is 1200012100201.

It is an a-pointer prime, because the next prime (1020012100031) can be obtained adding 1020012100021 to its sum of digits (10).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 804813528996 + 215198571025 = 897114^2 + 463895^2 .

It is a cyclic number.

It is not a de Polignac number, because 1020012100021 - 2¹³ = 1020012091829 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1020012099980 and 1020012100007.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1020012100001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 510006050010 + 510006050011.

It is an arithmetic number, because the mean of its divisors is an integer number (510006050011).

Almost surely, 2^{1020012100021} is an apocalyptic number.

It is an amenable number.

1020012100021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1020012100021 is an equidigital number, since it uses as much as digits as its factorization.

1020012100021 is an odious number, because the sum of its binary digits is odd.

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

Adding to 1020012100021 its reverse (1200012100201), we get a palindrome (2220024200222).

It can be divided in two parts, 102001 and 2100021, that added together give a palindrome (2202022).

The spelling of 1020012100021 in words is "one trillion, twenty billion, twelve million, one hundred thousand, twenty-one".