6531136421 has 2 divisors, whose sum is σ = 6531136422. Its totient is φ = 6531136420.

The previous prime is 6531136411. The next prime is 6531136457. The reversal of 6531136421 is 1246311356.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4133075521 + 2398060900 = 64289^2 + 48970^2 .

It is a cyclic number.

It is not a de Polignac number, because 6531136421 - 2⁶ = 6531136357 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6531136411) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3265568210 + 3265568211.

It is an arithmetic number, because the mean of its divisors is an integer number (3265568211).

Almost surely, 2^6531136421 is an apocalyptic number.

It is an amenable number.

6531136421 is a deficient number, since it is larger than the sum of its proper divisors (1).

6531136421 is an equidigital number, since it uses as much as digits as its factorization.

6531136421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12960, while the sum is 32.

The square root of 6531136421 is about 80815.4466732691. The cubic root of 6531136421 is about 1869.2307569392.

Adding to 6531136421 its reverse (1246311356), we get a palindrome (7777447777).

The spelling of 6531136421 in words is "six billion, five hundred thirty-one million, one hundred thirty-six thousand, four hundred twenty-one".