102906821 has 2 divisors, whose sum is σ = 102906822. Its totient is φ = 102906820.

The previous prime is 102906809. The next prime is 102906823. The reversal of 102906821 is 128609201.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 96805921 + 6100900 = 9839^2 + 2470^2 .

It is a cyclic number.

It is not a de Polignac number, because 102906821 - 2¹⁸ = 102644677 is a prime.

Together with 102906823, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (102906823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 51453410 + 51453411.

It is an arithmetic number, because the mean of its divisors is an integer number (51453411).

Almost surely, 2^102906821 is an apocalyptic number.

It is an amenable number.

102906821 is a deficient number, since it is larger than the sum of its proper divisors (1).

102906821 is an equidigital number, since it uses as much as digits as its factorization.

102906821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1728, while the sum is 29.

The square root of 102906821 is about 10144.2999265597. The cubic root of 102906821 is about 468.6134190286.

The spelling of 102906821 in words is "one hundred two million, nine hundred six thousand, eight hundred twenty-one".