102110821 has 2 divisors, whose sum is σ = 102110822. Its totient is φ = 102110820.

The previous prime is 102110819. The next prime is 102110831. The reversal of 102110821 is 128011201.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 76212900 + 25897921 = 8730^2 + 5089^2 .

It is a cyclic number.

It is not a de Polignac number, because 102110821 - 2¹ = 102110819 is a prime.

Together with 102110819, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 102110795 and 102110804.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (102110831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 51055410 + 51055411.

It is an arithmetic number, because the mean of its divisors is an integer number (51055411).

Almost surely, 2^102110821 is an apocalyptic number.

It is an amenable number.

102110821 is a deficient number, since it is larger than the sum of its proper divisors (1).

102110821 is an equidigital number, since it uses as much as digits as its factorization.

102110821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32, while the sum is 16.

The square root of 102110821 is about 10104.9899059821. The cubic root of 102110821 is about 467.4020247085.

The spelling of 102110821 in words is "one hundred two million, one hundred ten thousand, eight hundred twenty-one".