139781839 has 4 divisors (see below), whose sum is σ = 140619024. Its totient is φ = 138944656.

The previous prime is 139781813. The next prime is 139781843. The reversal of 139781839 is 938187931.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 938187931 = 2099 ⋅446969.

It is a cyclic number.

It is not a de Polignac number, because 139781839 - 2¹⁹ = 139257551 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 139781792 and 139781801.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (139781809) 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, 418342 + ... + 418675.

It is an arithmetic number, because the mean of its divisors is an integer number (35154756).

Almost surely, 2^139781839 is an apocalyptic number.

139781839 is a deficient number, since it is larger than the sum of its proper divisors (837185).

139781839 is an equidigital number, since it uses as much as digits as its factorization.

139781839 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 837184.

The product of its digits is 326592, while the sum is 49.

The square root of 139781839 is about 11822.9369870604. The cubic root of 139781839 is about 518.9795557501.

The spelling of 139781839 in words is "one hundred thirty-nine million, seven hundred eighty-one thousand, eight hundred thirty-nine".