139961 has 4 divisors (see below), whose sum is σ = 148212. Its totient is φ = 131712.

The previous prime is 139943. The next prime is 139967. The reversal of 139961 is 169931.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 169931 = 109 ⋅1559.

It can be written as a sum of positive squares in 2 ways, for example, as 67600 + 72361 = 260^2 + 269^2 .

It is a cyclic number.

It is not a de Polignac number, because 139961 - 2¹⁰ = 138937 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (139967) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4100 + ... + 4133.

It is an arithmetic number, because the mean of its divisors is an integer number (37053).

2¹³⁹⁹⁶¹ is an apocalyptic number.

It is an amenable number.

139961 is a deficient number, since it is larger than the sum of its proper divisors (8251).

139961 is an equidigital number, since it uses as much as digits as its factorization.

139961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8250.

The product of its digits is 1458, while the sum is 29.

The square root of 139961 is about 374.1136191052. The cubic root of 139961 is about 51.9201189691.

The spelling of 139961 in words is "one hundred thirty-nine thousand, nine hundred sixty-one".