6649781273 has 2 divisors, whose sum is σ = 6649781274. Its totient is φ = 6649781272.

The previous prime is 6649781269. The next prime is 6649781293. The reversal of 6649781273 is 3721879466.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5303771929 + 1346009344 = 72827^2 + 36688^2 .

It is a cyclic number.

It is not a de Polignac number, because 6649781273 - 2² = 6649781269 is a prime.

It is not a weakly prime, because it can be changed into another prime (6649781233) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3324890636 + 3324890637.

It is an arithmetic number, because the mean of its divisors is an integer number (3324890637).

Almost surely, 2^6649781273 is an apocalyptic number.

It is an amenable number.

6649781273 is a deficient number, since it is larger than the sum of its proper divisors (1).

6649781273 is an equidigital number, since it uses as much as digits as its factorization.

6649781273 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3048192, while the sum is 53.

The square root of 6649781273 is about 81546.1910391896. The cubic root of 6649781273 is about 1880.4817379664.

The spelling of 6649781273 in words is "six billion, six hundred forty-nine million, seven hundred eighty-one thousand, two hundred seventy-three".