138785918281 has 2 divisors, whose sum is σ = 138785918282. Its totient is φ = 138785918280.

The previous prime is 138785918279. The next prime is 138785918291. The reversal of 138785918281 is 182819587831.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 108955447056 + 29830471225 = 330084^2 + 172715^2 .

It is an emirp because it is prime and its reverse (182819587831) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 138785918281 - 2¹ = 138785918279 is a prime.

It is a super-2 number, since 2×138785918281² (a number of 23 digits) contains 22 as substring.

Together with 138785918279, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (138785918291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69392959140 + 69392959141.

It is an arithmetic number, because the mean of its divisors is an integer number (69392959141).

Almost surely, 2^138785918281 is an apocalyptic number.

It is an amenable number.

138785918281 is a deficient number, since it is larger than the sum of its proper divisors (1).

138785918281 is an equidigital number, since it uses as much as digits as its factorization.

138785918281 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7741440, while the sum is 61.

The spelling of 138785918281 in words is "one hundred thirty-eight billion, seven hundred eighty-five million, nine hundred eighteen thousand, two hundred eighty-one".