6531223991 has 2 divisors, whose sum is σ = 6531223992. Its totient is φ = 6531223990.

The previous prime is 6531223987. The next prime is 6531224071. The reversal of 6531223991 is 1993221356.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 6531223991 - 2² = 6531223987 is a prime.

It is a super-2 number, since 2×6531223991² = 85313773641227936162, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6531223921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3265611995 + 3265611996.

It is an arithmetic number, because the mean of its divisors is an integer number (3265611996).

Almost surely, 2^6531223991 is an apocalyptic number.

6531223991 is a deficient number, since it is larger than the sum of its proper divisors (1).

6531223991 is an equidigital number, since it uses as much as digits as its factorization.

6531223991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 87480, while the sum is 41.

The square root of 6531223991 is about 80815.9884614425. The cubic root of 6531223991 is about 1869.2391111671.

The spelling of 6531223991 in words is "six billion, five hundred thirty-one million, two hundred twenty-three thousand, nine hundred ninety-one".