• 139 can be written using four 4's:

139 has 2 divisors, whose sum is σ = 140. Its totient is φ = 138.

The previous prime is 137. The next prime is 149. The reversal of 139 is 931.

139 = 2^{2} + 3^{2} + ... + 7^{2}.

It is a happy number.

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

139 is an esthetic number in base 13, because in such base its adjacent digits differ by 1.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 139 - 2^{1} = 137 is a prime.

Together with 137, it forms a pair of twin primes.

It is a Chen prime.

It is a plaindrome in base 7, base 10, base 11, base 14 and base 16.

It is a nialpdrome in base 12, base 13 and base 15.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69 + 70.

It is an arithmetic number, because the mean of its divisors is an integer number (70).

139 is a deficient number, since it is larger than the sum of its proper divisors (1).

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

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

The product of its digits is 27, while the sum is 13.

The square root of 139 is about 11.7898261226. The cubic root of 139 is about 5.1801014674.

It can be divided in two parts, 13 and 9, that added together give a palindrome (22).

The spelling of 139 in words is "one hundred thirty-nine", and thus it is an aban number.

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