6561131 has 4 divisors (see below), whose sum is σ = 6567264. Its totient is φ = 6555000.

The previous prime is 6561127. The next prime is 6561143. The reversal of 6561131 is 1311656.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 6561131 - 2² = 6561127 is a prime.

It is a super-2 number, since 2×6561131² = 86096879998322, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 6561097 and 6561106.

It is not an unprimeable number, because it can be changed into a prime (6561151) 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, 995 + ... + 3756.

It is an arithmetic number, because the mean of its divisors is an integer number (1641816).

Almost surely, 2^6561131 is an apocalyptic number.

6561131 is a deficient number, since it is larger than the sum of its proper divisors (6133).

6561131 is a wasteful number, since it uses less digits than its factorization.

6561131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6132.

The product of its digits is 540, while the sum is 23.

The square root of 6561131 is about 2561.4704761133. The cubic root of 6561131 is about 187.2087900242.

Adding to 6561131 its reverse (1311656), we get a palindrome (7872787).

The spelling of 6561131 in words is "six million, five hundred sixty-one thousand, one hundred thirty-one".