6815815381 has 4 divisors (see below), whose sum is σ = 6816821152. Its totient is φ = 6814809612.

The previous prime is 6815815379. The next prime is 6815815417. The reversal of 6815815381 is 1835185186.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 6815815381 - 2¹ = 6815815379 is a prime.

It is a super-2 number, since 2×6815815381² = 92910678615752350322, 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 (6815815351) 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, 492651 + ... + 506296.

It is an arithmetic number, because the mean of its divisors is an integer number (1704205288).

Almost surely, 2^6815815381 is an apocalyptic number.

It is an amenable number.

6815815381 is a deficient number, since it is larger than the sum of its proper divisors (1005771).

6815815381 is an equidigital number, since it uses as much as digits as its factorization.

6815815381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1005770.

The product of its digits is 230400, while the sum is 46.

The square root of 6815815381 is about 82557.9516521576. The cubic root of 6815815381 is about 1896.0041026582.

The spelling of 6815815381 in words is "six billion, eight hundred fifteen million, eight hundred fifteen thousand, three hundred eighty-one".