139969 has 2 divisors, whose sum is σ = 139970. Its totient is φ = 139968.

The previous prime is 139967. The next prime is 139981. The reversal of 139969 is 969931.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 82369 + 57600 = 287^2 + 240^2 .

It is a cyclic number.

It is not a de Polignac number, because 139969 - 2¹ = 139967 is a prime.

It is a super-2 number, since 2×139969² = 39182641922, which contains 22 as substring.

Together with 139967, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (139967) by changing a digit.

It is a Pierpont prime, being equal to 2⁶ ⋅ 3⁷ + 1.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69984 + 69985.

It is an arithmetic number, because the mean of its divisors is an integer number (69985).

139969 is a Friedman number, since it can be written as ((9+9)*6)^3/9+1, using all its digits and the basic arithmetic operations.

2¹³⁹⁹⁶⁹ is an apocalyptic number.

It is an amenable number.

139969 is a deficient number, since it is larger than the sum of its proper divisors (1).

139969 is an equidigital number, since it uses as much as digits as its factorization.

139969 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13122, while the sum is 37.

The square root of 139969 is about 374.1243108914. The cubic root of 139969 is about 51.9211081804.

The spelling of 139969 in words is "one hundred thirty-nine thousand, nine hundred sixty-nine".