84217091909 has 2 divisors, whose sum is σ = 84217091910. Its totient is φ = 84217091908.

The previous prime is 84217091869. The next prime is 84217091927. The reversal of 84217091909 is 90919071248.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 44095800100 + 40121291809 = 209990^2 + 200303^2 .

It is a cyclic number.

It is not a de Polignac number, because 84217091909 - 2¹⁶ = 84217026373 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (84217091999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42108545954 + 42108545955.

It is an arithmetic number, because the mean of its divisors is an integer number (42108545955).

Almost surely, 2^84217091909 is an apocalyptic number.

It is an amenable number.

84217091909 is a deficient number, since it is larger than the sum of its proper divisors (1).

84217091909 is an equidigital number, since it uses as much as digits as its factorization.

84217091909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 326592, while the sum is 50.

The spelling of 84217091909 in words is "eighty-four billion, two hundred seventeen million, ninety-one thousand, nine hundred nine".