102020021 has 2 divisors, whose sum is σ = 102020022. Its totient is φ = 102020020.

The previous prime is 102019997. The next prime is 102020053. The reversal of 102020021 is 120020201.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 91202500 + 10817521 = 9550^2 + 3289^2 .

It is a cyclic number.

It is not a de Polignac number, because 102020021 - 2¹⁰ = 102018997 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 102019990 and 102020008.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (102020921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 51010010 + 51010011.

It is an arithmetic number, because the mean of its divisors is an integer number (51010011).

Almost surely, 2^102020021 is an apocalyptic number.

It is an amenable number.

102020021 is a deficient number, since it is larger than the sum of its proper divisors (1).

102020021 is an equidigital number, since it uses as much as digits as its factorization.

102020021 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.

The square root of 102020021 is about 10100.4960769261. The cubic root of 102020021 is about 467.2634409969.

Adding to 102020021 its reverse (120020201), we get a palindrome (222040222).

The spelling of 102020021 in words is "one hundred two million, twenty thousand, twenty-one".