139967561 has 4 divisors (see below), whose sum is σ = 140349312. Its totient is φ = 139585812.

The previous prime is 139967533. The next prime is 139967587. The reversal of 139967561 is 165769931.

It is a happy number.

139967561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 165769931 = 179 ⋅926089.

It is a cyclic number.

It is not a de Polignac number, because 139967561 - 2¹⁰ = 139966537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (139967501) 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, 190325 + ... + 191058.

It is an arithmetic number, because the mean of its divisors is an integer number (35087328).

Almost surely, 2^139967561 is an apocalyptic number.

It is an amenable number.

139967561 is a deficient number, since it is larger than the sum of its proper divisors (381751).

139967561 is an equidigital number, since it uses as much as digits as its factorization.

139967561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 381750.

The product of its digits is 306180, while the sum is 47.

The square root of 139967561 is about 11830.7886888407. The cubic root of 139967561 is about 519.2093024881.

The spelling of 139967561 in words is "one hundred thirty-nine million, nine hundred sixty-seven thousand, five hundred sixty-one".