139857639 has 4 divisors (see below), whose sum is σ = 186476856. Its totient is φ = 93238424.

The previous prime is 139857637. The next prime is 139857703. The reversal of 139857639 is 936758931.

139857639 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 936758931 = 3 ⋅312252977.

It is a cyclic number.

It is not a de Polignac number, because 139857639 - 2¹ = 139857637 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 139857591 and 139857600.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (139857637) 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, 23309604 + ... + 23309609.

It is an arithmetic number, because the mean of its divisors is an integer number (46619214).

Almost surely, 2^139857639 is an apocalyptic number.

139857639 is a deficient number, since it is larger than the sum of its proper divisors (46619217).

139857639 is an equidigital number, since it uses as much as digits as its factorization.

139857639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46619216.

The product of its digits is 1224720, while the sum is 51.

The square root of 139857639 is about 11826.1421858525. The cubic root of 139857639 is about 519.0733484345.

The spelling of 139857639 in words is "one hundred thirty-nine million, eight hundred fifty-seven thousand, six hundred thirty-nine".