139021 has 2 divisors, whose sum is σ = 139022. Its totient is φ = 139020.

The previous prime is 138977. The next prime is 139033. The reversal of 139021 is 120931.

139021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 126025 + 12996 = 355^2 + 114^2 .

It is a cyclic number.

It is not a de Polignac number, because 139021 - 2⁷ = 138893 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 138986 and 139004.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (139091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69510 + 69511.

It is an arithmetic number, because the mean of its divisors is an integer number (69511).

2¹³⁹⁰²¹ is an apocalyptic number.

It is an amenable number.

139021 is a deficient number, since it is larger than the sum of its proper divisors (1).

139021 is an equidigital number, since it uses as much as digits as its factorization.

139021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 54, while the sum is 16.

The square root of 139021 is about 372.8551997760. The cubic root of 139021 is about 51.8036232266.

Adding to 139021 its reverse (120931), we get a palindrome (259952).

The spelling of 139021 in words is "one hundred thirty-nine thousand, twenty-one".