139561281 has 6 divisors (see below), whose sum is σ = 201588530. Its totient is φ = 93040848.

The previous prime is 139561267. The next prime is 139561337. The reversal of 139561281 is 182165931.

139561281 is a `hidden beast` number, since 1 + 39 + 5 + 612 + 8 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 120560400 + 19000881 = 10980^2 + 4359^2 .

It is not a de Polignac number, because 139561281 - 2⁵ = 139561249 is a prime.

It is a super-3 number, since 3×139561281³ (a number of 25 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (139561231) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 7753396 + ... + 7753413.

Almost surely, 2^139561281 is an apocalyptic number.

It is an amenable number.

139561281 is a deficient number, since it is larger than the sum of its proper divisors (62027249).

139561281 is a wasteful number, since it uses less digits than its factorization.

139561281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15506815 (or 15506812 counting only the distinct ones).

The product of its digits is 12960, while the sum is 36.

The square root of 139561281 is about 11813.6057577693. The cubic root of 139561281 is about 518.7064507691.

The spelling of 139561281 in words is "one hundred thirty-nine million, five hundred sixty-one thousand, two hundred eighty-one".