139999 has 2 divisors, whose sum is σ = 140000. Its totient is φ = 139998.

The previous prime is 139991. The next prime is 140009. The reversal of 139999 is 999931.

It is a weak prime.

It is an emirp because it is prime and its reverse (999931) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 139999 - 2³ = 139991 is a prime.

139999 is a modest number, since divided by 999 gives 139 as remainder.

It is a plaindrome in base 10 and base 16.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (139991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69999 + 70000.

It is an arithmetic number, because the mean of its divisors is an integer number (70000).

2¹³⁹⁹⁹⁹ is an apocalyptic number.

139999 is a deficient number, since it is larger than the sum of its proper divisors (1).

139999 is an equidigital number, since it uses as much as digits as its factorization.

139999 is an evil number, because the sum of its binary digits is even.

The product of its digits is 19683, while the sum is 40.

The square root of 139999 is about 374.1644023688. The cubic root of 139999 is about 51.9248173874.

It can be divided in two parts, 1 and 39999, that added together give a square (40000 = 200²).

The spelling of 139999 in words is "one hundred thirty-nine thousand, nine hundred ninety-nine".