6531381 has 8 divisors (see below), whose sum is σ = 9676160. Its totient is φ = 4354236.

The previous prime is 6531377. The next prime is 6531391. The reversal of 6531381 is 1831356.

6531381 is a `hidden beast` number, since 653 + 1 + 3 + 8 + 1 = 666.

It is not a de Polignac number, because 6531381 - 2² = 6531377 is a prime.

It is a super-3 number, since 3×6531381³ (a number of 21 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 241903 = 6531381 / (6 + 5 + 3 + 1 + 3 + 8 + 1).

It is a Duffinian number.

6531381 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6531391) 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, 120925 + ... + 120978.

It is an arithmetic number, because the mean of its divisors is an integer number (1209520).

Almost surely, 2^6531381 is an apocalyptic number.

It is an amenable number.

6531381 is a deficient number, since it is larger than the sum of its proper divisors (3144779).

6531381 is a wasteful number, since it uses less digits than its factorization.

6531381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 241912 (or 241906 counting only the distinct ones).

The product of its digits is 2160, while the sum is 27.

The square root of 6531381 is about 2555.6566670819. The cubic root of 6531381 is about 186.9254089728.

The spelling of 6531381 in words is "six million, five hundred thirty-one thousand, three hundred eighty-one".