823387139 has 4 divisors (see below), whose sum is σ = 824829720. Its totient is φ = 821944560.

The previous prime is 823387087. The next prime is 823387151. The reversal of 823387139 is 931783328.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-823387139 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 823387139.

It is not an unprimeable number, because it can be changed into a prime (823387039) 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, 720434 + ... + 721575.

It is an arithmetic number, because the mean of its divisors is an integer number (206207430).

Almost surely, 2^823387139 is an apocalyptic number.

823387139 is a deficient number, since it is larger than the sum of its proper divisors (1442581).

823387139 is a wasteful number, since it uses less digits than its factorization.

823387139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1442580.

The product of its digits is 217728, while the sum is 44.

The square root of 823387139 is about 28694.7231908586. The cubic root of 823387139 is about 937.2771434489.

The spelling of 823387139 in words is "eight hundred twenty-three million, three hundred eighty-seven thousand, one hundred thirty-nine".