309438893681 has 2 divisors, whose sum is σ = 309438893682. Its totient is φ = 309438893680.

The previous prime is 309438893677. The next prime is 309438893711. The reversal of 309438893681 is 186398834903.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 166660714081 + 142778179600 = 408241^2 + 377860^2 .

It is an emirp because it is prime and its reverse (186398834903) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 309438893681 - 2² = 309438893677 is a prime.

It is a super-2 number, since 2×309438893681² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (309438893641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 154719446840 + 154719446841.

It is an arithmetic number, because the mean of its divisors is an integer number (154719446841).

Almost surely, 2^309438893681 is an apocalyptic number.

It is an amenable number.

309438893681 is a deficient number, since it is larger than the sum of its proper divisors (1).

309438893681 is an equidigital number, since it uses as much as digits as its factorization.

309438893681 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 26873856, while the sum is 62.

The spelling of 309438893681 in words is "three hundred nine billion, four hundred thirty-eight million, eight hundred ninety-three thousand, six hundred eighty-one".