856613381 has 8 divisors (see below), whose sum is σ = 947439864. Its totient is φ = 769348800.

The previous prime is 856613377. The next prime is 856613413. The reversal of 856613381 is 183316658.

It can be written as a sum of positive squares in 4 ways, for example, as 167288356 + 689325025 = 12934^2 + 26255^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 856613381 - 2² = 856613377 is a prime.

It is a super-2 number, since 2×856613381² = 1467572969016502322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (856613321) 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 7 ways as a sum of consecutive naturals, for example, 889970 + ... + 890931.

It is an arithmetic number, because the mean of its divisors is an integer number (118429983).

Almost surely, 2^856613381 is an apocalyptic number.

It is an amenable number.

856613381 is a deficient number, since it is larger than the sum of its proper divisors (90826483).

856613381 is a wasteful number, since it uses less digits than its factorization.

856613381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1780951.

The product of its digits is 103680, while the sum is 41.

The square root of 856613381 is about 29267.9582649696. The cubic root of 856613381 is about 949.7186169416.

The spelling of 856613381 in words is "eight hundred fifty-six million, six hundred thirteen thousand, three hundred eighty-one".