8121889 has 2 divisors, whose sum is σ = 8121890.
Its totient is φ = 8121888.
The previous prime is 8121887. The next prime is 8121901. The reversal of 8121889 is 9881218.
It can be divided in two parts, 812 and 1889, that added together give a triangular number (2701 = T73).
8121889 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.
It is a weak prime.
It can be written as a sum of positive squares in only one way, i.e., 6760000 + 1361889 = 2600^2 + 1167^2
It is a cyclic number.
It is not a de Polignac number, because 8121889 - 21 = 8121887 is a prime.
Together with 8121887, it forms a pair of twin primes.
It is a Chen prime.
It is not a weakly prime, because it can be changed into another prime (8121887) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4060944 + 4060945.
It is an arithmetic number, because the mean of its divisors is an integer number (4060945).
Almost surely, 28121889 is an apocalyptic number.
It is an amenable number.
8121889 is a deficient number, since it is larger than the sum of its proper divisors (1).
8121889 is an equidigital number, since it uses as much as digits as its factorization.
8121889 is an evil number, because the sum of its binary digits is even.
The product of its digits is 9216, while the sum is 37.
The square root of 8121889 is about 2849.8928050016.
The cubic root of 8121889 is about 201.0106262379.
The spelling of 8121889 in words is "eight million, one hundred twenty-one thousand, eight hundred eighty-nine".