139986421 has 4 divisors (see below), whose sum is σ = 144502144. Its totient is φ = 135470700.

The previous prime is 139986419. The next prime is 139986437. The reversal of 139986421 is 124689931.

It is a happy number.

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: 124689931 = 10223 ⋅12197.

It is a cyclic number.

It is not a de Polignac number, because 139986421 - 2¹ = 139986419 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (139986461) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2257815 + ... + 2257876.

It is an arithmetic number, because the mean of its divisors is an integer number (36125536).

Almost surely, 2^139986421 is an apocalyptic number.

It is an amenable number.

139986421 is a deficient number, since it is larger than the sum of its proper divisors (4515723).

139986421 is an equidigital number, since it uses as much as digits as its factorization.

139986421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4515722.

The product of its digits is 93312, while the sum is 43.

The square root of 139986421 is about 11831.5857348033. The cubic root of 139986421 is about 519.2326218144.

The spelling of 139986421 in words is "one hundred thirty-nine million, nine hundred eighty-six thousand, four hundred twenty-one".