139685261 has 4 divisors (see below), whose sum is σ = 139773792. Its totient is φ = 139596732.

The previous prime is 139685251. The next prime is 139685267. The reversal of 139685261 is 162586931.

139685261 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.

It is a cyclic number.

It is not a de Polignac number, because 139685261 - 2¹⁸ = 139423117 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 (139685267) 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, 41855 + ... + 45068.

It is an arithmetic number, because the mean of its divisors is an integer number (34943448).

Almost surely, 2^139685261 is an apocalyptic number.

It is an amenable number.

139685261 is a deficient number, since it is larger than the sum of its proper divisors (88531).

139685261 is an equidigital number, since it uses as much as digits as its factorization.

139685261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 88530.

The product of its digits is 77760, while the sum is 41.

The square root of 139685261 is about 11818.8519324002. The cubic root of 139685261 is about 518.8600038452.

The spelling of 139685261 in words is "one hundred thirty-nine million, six hundred eighty-five thousand, two hundred sixty-one".