139557581 has 2 divisors, whose sum is σ = 139557582. Its totient is φ = 139557580.

The previous prime is 139557571. The next prime is 139557601. The reversal of 139557581 is 185755931.

It is a happy number.

139557581 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 94264681 + 45292900 = 9709^2 + 6730^2 .

It is an emirp because it is prime and its reverse (185755931) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 139557581 - 2¹⁸ = 139295437 is a prime.

It is a super-2 number, since 2×139557581² = 38952636829143122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (139557521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69778790 + 69778791.

It is an arithmetic number, because the mean of its divisors is an integer number (69778791).

Almost surely, 2^139557581 is an apocalyptic number.

It is an amenable number.

139557581 is a deficient number, since it is larger than the sum of its proper divisors (1).

139557581 is an equidigital number, since it uses as much as digits as its factorization.

139557581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 189000, while the sum is 44.

The square root of 139557581 is about 11813.4491576339. The cubic root of 139557581 is about 518.7018668071.

The spelling of 139557581 in words is "one hundred thirty-nine million, five hundred fifty-seven thousand, five hundred eighty-one".