2609321681 has 2 divisors, whose sum is σ = 2609321682. Its totient is φ = 2609321680.

The previous prime is 2609321579. The next prime is 2609321747. The reversal of 2609321681 is 1861239062.

It is a happy number.

2609321681 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2387788225 + 221533456 = 48865^2 + 14884^2 .

It is a cyclic number.

It is not a de Polignac number, because 2609321681 - 2¹⁰ = 2609320657 is a prime.

It is a super-2 number, since 2×2609321681² = 13617119269873331522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (2609341681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1304660840 + 1304660841.

It is an arithmetic number, because the mean of its divisors is an integer number (1304660841).

Almost surely, 2^2609321681 is an apocalyptic number.

It is an amenable number.

2609321681 is a deficient number, since it is larger than the sum of its proper divisors (1).

2609321681 is an equidigital number, since it uses as much as digits as its factorization.

2609321681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 31104, while the sum is 38.

The square root of 2609321681 is about 51081.5199558510. The cubic root of 2609321681 is about 1376.7102344072.

It can be divided in two parts, 26093 and 21681, that added together give a palindrome (47774).

The spelling of 2609321681 in words is "two billion, six hundred nine million, three hundred twenty-one thousand, six hundred eighty-one".