6688570781 has 2 divisors, whose sum is σ = 6688570782. Its totient is φ = 6688570780.

The previous prime is 6688570753. The next prime is 6688570829. The reversal of 6688570781 is 1870758866.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4601451556 + 2087119225 = 67834^2 + 45685^2 .

It is a cyclic number.

It is not a de Polignac number, because 6688570781 - 2⁶ = 6688570717 is a prime.

It is a super-2 number, since 2×6688570781² = 89473958184893899922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6688570081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3344285390 + 3344285391.

It is an arithmetic number, because the mean of its divisors is an integer number (3344285391).

Almost surely, 2^6688570781 is an apocalyptic number.

It is an amenable number.

6688570781 is a deficient number, since it is larger than the sum of its proper divisors (1).

6688570781 is an equidigital number, since it uses as much as digits as its factorization.

6688570781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4515840, while the sum is 56.

The square root of 6688570781 is about 81783.6828529995. The cubic root of 6688570781 is about 1884.1310604512.

The spelling of 6688570781 in words is "six billion, six hundred eighty-eight million, five hundred seventy thousand, seven hundred eighty-one".