856742919 has 4 divisors (see below), whose sum is σ = 1142323896. Its totient is φ = 571161944.

The previous prime is 856742917. The next prime is 856742963. The reversal of 856742919 is 919247658.

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

It is a cyclic number.

It is not a de Polignac number, because 856742919 - 2¹ = 856742917 is a prime.

It is a super-2 number, since 2×856742919² = 1468016858513281122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (856742917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 142790484 + ... + 142790489.

It is an arithmetic number, because the mean of its divisors is an integer number (285580974).

Almost surely, 2^856742919 is an apocalyptic number.

856742919 is a deficient number, since it is larger than the sum of its proper divisors (285580977).

856742919 is a wasteful number, since it uses less digits than its factorization.

856742919 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 285580976.

The product of its digits is 1088640, while the sum is 51.

The square root of 856742919 is about 29270.1711474327. The cubic root of 856742919 is about 949.7664870201.

The spelling of 856742919 in words is "eight hundred fifty-six million, seven hundred forty-two thousand, nine hundred nineteen".