139581 has 12 divisors (see below), whose sum is σ = 217308. Its totient is φ = 85824.

The previous prime is 139571. The next prime is 139589. The reversal of 139581 is 185931.

It can be written as a sum of positive squares in 2 ways, for example, as 44100 + 95481 = 210^2 + 309^2 .

It is a de Polignac number, because none of the positive numbers 2^k-139581 is a prime.

It is a super-2 number, since 2×139581² = 38965711122, which contains 22 as substring.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 139581.

It is not an unprimeable number, because it can be changed into a prime (139589) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 480 + ... + 713.

It is an arithmetic number, because the mean of its divisors is an integer number (18109).

2¹³⁹⁵⁸¹ is an apocalyptic number.

It is an amenable number.

139581 is a deficient number, since it is larger than the sum of its proper divisors (77727).

139581 is a wasteful number, since it uses less digits than its factorization.

139581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1212 (or 1209 counting only the distinct ones).

The product of its digits is 1080, while the sum is 27.

The square root of 139581 is about 373.6054068131. The cubic root of 139581 is about 51.8730879442.

The spelling of 139581 in words is "one hundred thirty-nine thousand, five hundred eighty-one".