138142681 has 2 divisors, whose sum is σ = 138142682. Its totient is φ = 138142680.

The previous prime is 138142679. The next prime is 138142687. The reversal of 138142681 is 186241831.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 137851081 + 291600 = 11741^2 + 540^2 .

It is a cyclic number.

It is not a de Polignac number, because 138142681 - 2¹ = 138142679 is a prime.

It is a super-2 number, since 2×138142681² = 38166800627735522, which contains 22 as substring.

Together with 138142679, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (138142687) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69071340 + 69071341.

It is an arithmetic number, because the mean of its divisors is an integer number (69071341).

Almost surely, 2^138142681 is an apocalyptic number.

It is an amenable number.

138142681 is a deficient number, since it is larger than the sum of its proper divisors (1).

138142681 is an equidigital number, since it uses as much as digits as its factorization.

138142681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9216, while the sum is 34.

The square root of 138142681 is about 11753.4114622096. The cubic root of 138142681 is about 516.9429618057.

The spelling of 138142681 in words is "one hundred thirty-eight million, one hundred forty-two thousand, six hundred eighty-one".