6217779991 has 2 divisors, whose sum is σ = 6217779992. Its totient is φ = 6217779990.

The previous prime is 6217779989. The next prime is 6217780007. The reversal of 6217779991 is 1999777126.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 6217779991 - 2¹ = 6217779989 is a prime.

Together with 6217779989, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6217779961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3108889995 + 3108889996.

It is an arithmetic number, because the mean of its divisors is an integer number (3108889996).

Almost surely, 2^6217779991 is an apocalyptic number.

6217779991 is a deficient number, since it is larger than the sum of its proper divisors (1).

6217779991 is an equidigital number, since it uses as much as digits as its factorization.

6217779991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3000564, while the sum is 58.

The square root of 6217779991 is about 78852.9009675611. The cubic root of 6217779991 is about 1838.8449736518.

The spelling of 6217779991 in words is "six billion, two hundred seventeen million, seven hundred seventy-nine thousand, nine hundred ninety-one".