856371509 has 8 divisors (see below), whose sum is σ = 997176960. Its totient is φ = 720182736.

The previous prime is 856371493. The next prime is 856371533. The reversal of 856371509 is 905173658.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 856371509 - 2⁴ = 856371493 is a prime.

It is a super-3 number, since 3×856371509³ (a number of 28 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

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 856371509.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (856371539) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1153769 + ... + 1154510.

It is an arithmetic number, because the mean of its divisors is an integer number (124647120).

Almost surely, 2^856371509 is an apocalyptic number.

It is an amenable number.

856371509 is a deficient number, since it is larger than the sum of its proper divisors (140805451).

856371509 is a wasteful number, since it uses less digits than its factorization.

856371509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2308339.

The product of its (nonzero) digits is 226800, while the sum is 44.

The square root of 856371509 is about 29263.8259460379. The cubic root of 856371509 is about 949.6292215115.

The spelling of 856371509 in words is "eight hundred fifty-six million, three hundred seventy-one thousand, five hundred nine".