851811381 has 24 divisors (see below), whose sum is σ = 1279682976. Its totient is φ = 545559840.

The previous prime is 851811349. The next prime is 851811383. The reversal of 851811381 is 183118158.

It is a happy number.

851811381 is a `hidden beast` number, since 8 + 518 + 1 + 138 + 1 = 666.

851811381 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 851811381 - 2⁵ = 851811349 is a prime.

It is a super-2 number, since 2×851811381² = 1451165257602254322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (851811383) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5566 + ... + 41648.

It is an arithmetic number, because the mean of its divisors is an integer number (53320124).

Almost surely, 2^851811381 is an apocalyptic number.

It is an amenable number.

851811381 is a deficient number, since it is larger than the sum of its proper divisors (427871595).

851811381 is a wasteful number, since it uses less digits than its factorization.

851811381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36193 (or 36190 counting only the distinct ones).

The product of its digits is 7680, while the sum is 36.

The square root of 851811381 is about 29185.8078695794. The cubic root of 851811381 is about 947.9406474885.

The spelling of 851811381 in words is "eight hundred fifty-one million, eight hundred eleven thousand, three hundred eighty-one".