139867681 has 2 divisors, whose sum is σ = 139867682. Its totient is φ = 139867680.

The previous prime is 139867649. The next prime is 139867697. The reversal of 139867681 is 186768931.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 121881600 + 17986081 = 11040^2 + 4241^2 .

It is an emirp because it is prime and its reverse (186768931) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 139867681 - 2⁵ = 139867649 is a prime.

It is a super-2 number, since 2×139867681² = 39125936376635522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (139867621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69933840 + 69933841.

It is an arithmetic number, because the mean of its divisors is an integer number (69933841).

Almost surely, 2^139867681 is an apocalyptic number.

It is an amenable number.

139867681 is a deficient number, since it is larger than the sum of its proper divisors (1).

139867681 is an equidigital number, since it uses as much as digits as its factorization.

139867681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 435456, while the sum is 49.

The square root of 139867681 is about 11826.5667461018. The cubic root of 139867681 is about 519.0857715666.

The spelling of 139867681 in words is "one hundred thirty-nine million, eight hundred sixty-seven thousand, six hundred eighty-one".