84681209 has 2 divisors, whose sum is σ = 84681210. Its totient is φ = 84681208.

The previous prime is 84681143. The next prime is 84681217. The reversal of 84681209 is 90218648.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 84640000 + 41209 = 9200^2 + 203^2 .

It is a cyclic number.

It is not a de Polignac number, because 84681209 - 2¹² = 84677113 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (84681269) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42340604 + 42340605.

It is an arithmetic number, because the mean of its divisors is an integer number (42340605).

Almost surely, 2^84681209 is an apocalyptic number.

It is an amenable number.

84681209 is a deficient number, since it is larger than the sum of its proper divisors (1).

84681209 is an equidigital number, since it uses as much as digits as its factorization.

84681209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 27648, while the sum is 38.

The square root of 84681209 is about 9202.2393470285. The cubic root of 84681209 is about 439.1326041959.

The spelling of 84681209 in words is "eighty-four million, six hundred eighty-one thousand, two hundred nine".