6815981 has 4 divisors (see below), whose sum is σ = 7112352. Its totient is φ = 6519612.

The previous prime is 6815971. The next prime is 6816011. The reversal of 6815981 is 1895186.

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 6815981 - 2¹⁰ = 6814957 is a prime.

It is a super-2 number, since 2×6815981² = 92915193984722, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6815911) 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, 148151 + ... + 148196.

It is an arithmetic number, because the mean of its divisors is an integer number (1778088).

Almost surely, 2^6815981 is an apocalyptic number.

It is an amenable number.

6815981 is a deficient number, since it is larger than the sum of its proper divisors (296371).

6815981 is a wasteful number, since it uses less digits than its factorization.

6815981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 296370.

The product of its digits is 17280, while the sum is 38.

The square root of 6815981 is about 2610.7433807251. The cubic root of 6815981 is about 189.6019459674.

The spelling of 6815981 in words is "six million, eight hundred fifteen thousand, nine hundred eighty-one".