102020000021 has 4 divisors (see below), whose sum is σ = 102764671692. Its totient is φ = 101275328352.

The previous prime is 102019999997. The next prime is 102020000087. The reversal of 102020000021 is 120000020201.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 88122891025 + 13897108996 = 296855^2 + 117886^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-102020000021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 102019999963 and 102020000008.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (102020000521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 372335630 + ... + 372335903.

It is an arithmetic number, because the mean of its divisors is an integer number (25691167923).

Almost surely, 2^102020000021 is an apocalyptic number.

It is an amenable number.

102020000021 is a deficient number, since it is larger than the sum of its proper divisors (744671671).

102020000021 is an equidigital number, since it uses as much as digits as its factorization.

102020000021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 744671670.

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

Adding to 102020000021 its reverse (120000020201), we get a palindrome (222020020222).

The spelling of 102020000021 in words is "one hundred two billion, twenty million, twenty-one", and thus it is an aban number.