309739396985 has 4 divisors (see below), whose sum is σ = 371687276388. Its totient is φ = 247791517584.

The previous prime is 309739396979. The next prime is 309739396987. The reversal of 309739396985 is 589693937903.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 589693937903 = 7 ⋅84241991129.

It can be written as a sum of positive squares in 2 ways, for example, as 69706032361 + 240033364624 = 264019^2 + 489932^2 .

It is a cyclic number.

It is not a de Polignac number, because 309739396985 - 2¹⁸ = 309739134841 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (309739396987) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30973939694 + ... + 30973939703.

It is an arithmetic number, because the mean of its divisors is an integer number (92921819097).

Almost surely, 2^309739396985 is an apocalyptic number.

It is an amenable number.

309739396985 is a deficient number, since it is larger than the sum of its proper divisors (61947879403).

309739396985 is an equidigital number, since it uses as much as digits as its factorization.

309739396985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61947879402.

The product of its (nonzero) digits is 297606960, while the sum is 71.

The spelling of 309739396985 in words is "three hundred nine billion, seven hundred thirty-nine million, three hundred ninety-six thousand, nine hundred eighty-five".