6540143261 has 4 divisors (see below), whose sum is σ = 6540368892. Its totient is φ = 6539917632.

The previous prime is 6540143251. The next prime is 6540143279. The reversal of 6540143261 is 1623410456.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4979419225 + 1560724036 = 70565^2 + 39506^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6540143261 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6540143231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 61580 + ... + 129893.

It is an arithmetic number, because the mean of its divisors is an integer number (1635092223).

Almost surely, 2^6540143261 is an apocalyptic number.

It is an amenable number.

6540143261 is a deficient number, since it is larger than the sum of its proper divisors (225631).

6540143261 is a wasteful number, since it uses less digits than its factorization.

6540143261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 225630.

The product of its (nonzero) digits is 17280, while the sum is 32.

The square root of 6540143261 is about 80871.1522175862. The cubic root of 6540143261 is about 1870.0896237560.

The spelling of 6540143261 in words is "six billion, five hundred forty million, one hundred forty-three thousand, two hundred sixty-one".