309985478321 has 2 divisors, whose sum is σ = 309985478322. Its totient is φ = 309985478320.

The previous prime is 309985478219. The next prime is 309985478347. The reversal of 309985478321 is 123874589903.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 257114914225 + 52870564096 = 507065^2 + 229936^2 .

It is a cyclic number.

It is not a de Polignac number, because 309985478321 - 2¹⁴ = 309985461937 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (309985478921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 154992739160 + 154992739161.

It is an arithmetic number, because the mean of its divisors is an integer number (154992739161).

Almost surely, 2^309985478321 is an apocalyptic number.

It is an amenable number.

309985478321 is a deficient number, since it is larger than the sum of its proper divisors (1).

309985478321 is an equidigital number, since it uses as much as digits as its factorization.

309985478321 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13063680, while the sum is 59.

The spelling of 309985478321 in words is "three hundred nine billion, nine hundred eighty-five million, four hundred seventy-eight thousand, three hundred twenty-one".