2666720321 has 2 divisors, whose sum is σ = 2666720322. Its totient is φ = 2666720320.

The previous prime is 2666720299. The next prime is 2666720369. The reversal of 2666720321 is 1230276662.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2635795600 + 30924721 = 51340^2 + 5561^2 .

It is a cyclic number.

It is not a de Polignac number, because 2666720321 - 2²² = 2662526017 is a prime.

It is a super-2 number, since 2×2666720321² = 14222794540868686082, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (2666720821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1333360160 + 1333360161.

It is an arithmetic number, because the mean of its divisors is an integer number (1333360161).

Almost surely, 2^2666720321 is an apocalyptic number.

It is an amenable number.

2666720321 is a deficient number, since it is larger than the sum of its proper divisors (1).

2666720321 is an equidigital number, since it uses as much as digits as its factorization.

2666720321 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36288, while the sum is 35.

The square root of 2666720321 is about 51640.2974526677. The cubic root of 2666720321 is about 1386.7318490981.

Adding to 2666720321 its reverse (1230276662), we get a palindrome (3896996983).

The spelling of 2666720321 in words is "two billion, six hundred sixty-six million, seven hundred twenty thousand, three hundred twenty-one".