139421 has 4 divisors (see below), whose sum is σ = 140832. Its totient is φ = 138012.

The previous prime is 139409. The next prime is 139423. The reversal of 139421 is 124931.

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, and also an emirpimes, since its reverse is a distinct semiprime: 124931 = 271 ⋅461.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-139421 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 139393 and 139402.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 139421.

It is not an unprimeable number, because it can be changed into a prime (139423) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 545 + ... + 758.

It is an arithmetic number, because the mean of its divisors is an integer number (35208).

2¹³⁹⁴²¹ is an apocalyptic number.

It is an amenable number.

139421 is a deficient number, since it is larger than the sum of its proper divisors (1411).

139421 is a wasteful number, since it uses less digits than its factorization.

139421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1410.

The product of its digits is 216, while the sum is 20.

The square root of 139421 is about 373.3912157510. The cubic root of 139421 is about 51.8532598698.

The spelling of 139421 in words is "one hundred thirty-nine thousand, four hundred twenty-one".