2600641781 has 2 divisors, whose sum is σ = 2600641782. Its totient is φ = 2600641780.

The previous prime is 2600641753. The next prime is 2600641817. The reversal of 2600641781 is 1871460062.

Together with next prime (2600641817) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2513518225 + 87123556 = 50135^2 + 9334^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2600641781 is a prime.

It is a super-2 number, since 2×2600641781² = 13526675346165703922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2600641711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1300320890 + 1300320891.

It is an arithmetic number, because the mean of its divisors is an integer number (1300320891).

Almost surely, 2^2600641781 is an apocalyptic number.

It is an amenable number.

2600641781 is a deficient number, since it is larger than the sum of its proper divisors (1).

2600641781 is an equidigital number, since it uses as much as digits as its factorization.

2600641781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16128, while the sum is 35.

The square root of 2600641781 is about 50996.4879280917. The cubic root of 2600641781 is about 1375.1819979038.

The spelling of 2600641781 in words is "two billion, six hundred million, six hundred forty-one thousand, seven hundred eighty-one".