102102110021 has 4 divisors (see below), whose sum is σ = 102102749100. Its totient is φ = 102101470944.

The previous prime is 102102110009. The next prime is 102102110039. The reversal of 102102110021 is 120011201201.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 52723048225 + 49379061796 = 229615^2 + 222214^2 .

It is a cyclic number.

It is not a de Polignac number, because 102102110021 - 2⁶ = 102102109957 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 102102109984 and 102102110011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (102102110051) 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, 157145 + ... + 478433.

It is an arithmetic number, because the mean of its divisors is an integer number (25525687275).

Almost surely, 2^102102110021 is an apocalyptic number.

It is an amenable number.

102102110021 is a deficient number, since it is larger than the sum of its proper divisors (639079).

102102110021 is an equidigital number, since it uses as much as digits as its factorization.

102102110021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 639078.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 102102110021 its reverse (120011201201), we get a palindrome (222113311222).

The spelling of 102102110021 in words is "one hundred two billion, one hundred two million, one hundred ten thousand, twenty-one".