840142109 has 2 divisors, whose sum is σ = 840142110. Its totient is φ = 840142108.

The previous prime is 840142103. The next prime is 840142117. The reversal of 840142109 is 901241048.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 788374084 + 51768025 = 28078^2 + 7195^2 .

It is a cyclic number.

It is not a de Polignac number, because 840142109 - 2²⁰ = 839093533 is a prime.

It is equal to p_43102289 and since 840142109 and 43102289 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (840142103) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 420071054 + 420071055.

It is an arithmetic number, because the mean of its divisors is an integer number (420071055).

Almost surely, 2^840142109 is an apocalyptic number.

It is an amenable number.

840142109 is a deficient number, since it is larger than the sum of its proper divisors (1).

840142109 is an equidigital number, since it uses as much as digits as its factorization.

840142109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2304, while the sum is 29.

The square root of 840142109 is about 28985.2050018626. The cubic root of 840142109 is about 943.5920015371.

The spelling of 840142109 in words is "eight hundred forty million, one hundred forty-two thousand, one hundred nine".