816139 has 4 divisors (see below), whose sum is σ = 826056. Its totient is φ = 806224.

The previous prime is 816133. The next prime is 816157. The reversal of 816139 is 931618.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 931618 = 2 ⋅465809.

It is a cyclic number.

It is not a de Polignac number, because 816139 - 2³ = 816131 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (816131) 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, 4834 + ... + 4999.

It is an arithmetic number, because the mean of its divisors is an integer number (206514).

2⁸¹⁶¹³⁹ is an apocalyptic number.

816139 is a deficient number, since it is larger than the sum of its proper divisors (9917).

816139 is an equidigital number, since it uses as much as digits as its factorization.

816139 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9916.

The product of its digits is 1296, while the sum is 28.

The square root of 816139 is about 903.4041177679. The cubic root of 816139 is about 93.4518802601.

The spelling of 816139 in words is "eight hundred sixteen thousand, one hundred thirty-nine".