685156139 has 2 divisors, whose sum is σ = 685156140. Its totient is φ = 685156138.

The previous prime is 685156123. The next prime is 685156187. The reversal of 685156139 is 931651586.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 685156139 - 2⁴ = 685156123 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 685156139.

It is not a weakly prime, because it can be changed into another prime (685156189) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342578069 + 342578070.

It is an arithmetic number, because the mean of its divisors is an integer number (342578070).

Almost surely, 2^685156139 is an apocalyptic number.

685156139 is a deficient number, since it is larger than the sum of its proper divisors (1).

685156139 is an equidigital number, since it uses as much as digits as its factorization.

685156139 is an evil number, because the sum of its binary digits is even.

The product of its digits is 194400, while the sum is 44.

The square root of 685156139 is about 26175.4873689106. The cubic root of 685156139 is about 881.5829544882.

The spelling of 685156139 in words is "six hundred eighty-five million, one hundred fifty-six thousand, one hundred thirty-nine".