139949581 has 2 divisors, whose sum is σ = 139949582. Its totient is φ = 139949580.

The previous prime is 139949567. The next prime is 139949587. The reversal of 139949581 is 185949931.

139949581 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 111112681 + 28836900 = 10541^2 + 5370^2 .

It is a cyclic number.

It is not a de Polignac number, because 139949581 - 2¹⁵ = 139916813 is a prime.

It is a super-2 number, since 2×139949581² = 39171770444151122, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (139949587) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69974790 + 69974791.

It is an arithmetic number, because the mean of its divisors is an integer number (69974791).

Almost surely, 2^139949581 is an apocalyptic number.

It is an amenable number.

139949581 is a deficient number, since it is larger than the sum of its proper divisors (1).

139949581 is an equidigital number, since it uses as much as digits as its factorization.

139949581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 349920, while the sum is 49.

The square root of 139949581 is about 11830.0287827207. The cubic root of 139949581 is about 519.1870692817.

The spelling of 139949581 in words is "one hundred thirty-nine million, nine hundred forty-nine thousand, five hundred eighty-one".