15857139 has 4 divisors (see below), whose sum is σ = 21142856. Its totient is φ = 10571424.

The previous prime is 15857137. The next prime is 15857161. The reversal of 15857139 is 93175851.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 93175851 = 3 ⋅31058617.

It is not a de Polignac number, because 15857139 - 2¹ = 15857137 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 15857097 and 15857106.

It is not an unprimeable number, because it can be changed into a prime (15857137) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2642854 + ... + 2642859.

It is an arithmetic number, because the mean of its divisors is an integer number (5285714).

Almost surely, 2^15857139 is an apocalyptic number.

15857139 is a deficient number, since it is larger than the sum of its proper divisors (5285717).

15857139 is an equidigital number, since it uses as much as digits as its factorization.

15857139 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5285716.

The product of its digits is 37800, while the sum is 39.

The square root of 15857139 is about 3982.1023341948. The cubic root of 15857139 is about 251.2319934621.

The spelling of 15857139 in words is "fifteen million, eight hundred fifty-seven thousand, one hundred thirty-nine".