139085281 has 4 divisors (see below), whose sum is σ = 139113364. Its totient is φ = 139057200.

The previous prime is 139085269. The next prime is 139085291. The reversal of 139085281 is 182580931.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 182580931 = 13 ⋅14044687.

It can be written as a sum of positive squares in 2 ways, for example, as 41075281 + 98010000 = 6409^2 + 9900^2 .

It is a cyclic number.

It is not a de Polignac number, because 139085281 - 2⁵ = 139085249 is a prime.

It is a super-2 number, since 2×139085281² = 38689430781697922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 139085281.

It is not an unprimeable number, because it can be changed into a prime (139085291) 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 in 3 ways as a sum of consecutive naturals, for example, 4410 + ... + 17251.

It is an arithmetic number, because the mean of its divisors is an integer number (34778341).

Almost surely, 2^139085281 is an apocalyptic number.

It is an amenable number.

139085281 is a deficient number, since it is larger than the sum of its proper divisors (28083).

139085281 is an equidigital number, since it uses as much as digits as its factorization.

139085281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28082.

The product of its (nonzero) digits is 17280, while the sum is 37.

The square root of 139085281 is about 11793.4422879836. The cubic root of 139085281 is about 518.1160637449.

The spelling of 139085281 in words is "one hundred thirty-nine million, eighty-five thousand, two hundred eighty-one".