139840681 has 2 divisors, whose sum is σ = 139840682. Its totient is φ = 139840680.

The previous prime is 139840669. The next prime is 139840699. The reversal of 139840681 is 186048931.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 137264656 + 2576025 = 11716^2 + 1605^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-139840681 is a prime.

It is a super-2 number, since 2×139840681² = 39110832125087522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (139810681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69920340 + 69920341.

It is an arithmetic number, because the mean of its divisors is an integer number (69920341).

Almost surely, 2^139840681 is an apocalyptic number.

It is an amenable number.

139840681 is a deficient number, since it is larger than the sum of its proper divisors (1).

139840681 is an equidigital number, since it uses as much as digits as its factorization.

139840681 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 41472, while the sum is 40.

The square root of 139840681 is about 11825.4251932013. The cubic root of 139840681 is about 519.0523680487.

The spelling of 139840681 in words is "one hundred thirty-nine million, eight hundred forty thousand, six hundred eighty-one".