102122821 has 2 divisors, whose sum is σ = 102122822. Its totient is φ = 102122820.

The previous prime is 102122819. The next prime is 102122837. The reversal of 102122821 is 128221201.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 101808100 + 314721 = 10090^2 + 561^2 .

It is an emirp because it is prime and its reverse (128221201) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 102122821 - 2¹ = 102122819 is a prime.

Together with 102122819, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (102122851) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 51061410 + 51061411.

It is an arithmetic number, because the mean of its divisors is an integer number (51061411).

Almost surely, 2^102122821 is an apocalyptic number.

It is an amenable number.

102122821 is a deficient number, since it is larger than the sum of its proper divisors (1).

102122821 is an equidigital number, since it uses as much as digits as its factorization.

102122821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 128, while the sum is 19.

The square root of 102122821 is about 10105.5836545941. The cubic root of 102122821 is about 467.4203335895.

The spelling of 102122821 in words is "one hundred two million, one hundred twenty-two thousand, eight hundred twenty-one".