139405837 has 4 divisors (see below), whose sum is σ = 141315580. Its totient is φ = 137496096.

The previous prime is 139405823. The next prime is 139405841. The reversal of 139405837 is 738504931.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 738504931 = 1291 ⋅572041.

It can be written as a sum of positive squares in 2 ways, for example, as 112063396 + 27342441 = 10586^2 + 5229^2 .

It is a cyclic number.

It is not a de Polignac number, because 139405837 - 2⁷ = 139405709 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 139405837.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (139405817) 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, 954762 + ... + 954907.

It is an arithmetic number, because the mean of its divisors is an integer number (35328895).

Almost surely, 2^139405837 is an apocalyptic number.

It is an amenable number.

139405837 is a deficient number, since it is larger than the sum of its proper divisors (1909743).

139405837 is an equidigital number, since it uses as much as digits as its factorization.

139405837 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1909742.

The product of its (nonzero) digits is 90720, while the sum is 40.

The square root of 139405837 is about 11807.0249004565. The cubic root of 139405837 is about 518.5138000119.

The spelling of 139405837 in words is "one hundred thirty-nine million, four hundred five thousand, eight hundred thirty-seven".