21010102021 has 2 divisors, whose sum is σ = 21010102022. Its totient is φ = 21010102020.

The previous prime is 21010101977. The next prime is 21010102039. The reversal of 21010102021 is 12020101012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20782393921 + 227708100 = 144161^2 + 15090^2 .

It is a cyclic number.

It is not a de Polignac number, because 21010102021 - 2⁹ = 21010101509 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21010101989 and 21010102007.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21010102051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10505051010 + 10505051011.

It is an arithmetic number, because the mean of its divisors is an integer number (10505051011).

Almost surely, 2^21010102021 is an apocalyptic number.

It is an amenable number.

21010102021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21010102021 is an equidigital number, since it uses as much as digits as its factorization.

21010102021 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 10.

Adding to 21010102021 its reverse (12020101012), we get a palindrome (33030203033).

The spelling of 21010102021 in words is "twenty-one billion, ten million, one hundred two thousand, twenty-one".