7781889449749 has 2 divisors, whose sum is σ = 7781889449750. Its totient is φ = 7781889449748.

The previous prime is 7781889449731. The next prime is 7781889449753. The reversal of 7781889449749 is 9479449881877.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7646369752849 + 135519696900 = 2765207^2 + 368130^2 .

It is a cyclic number.

It is not a de Polignac number, because 7781889449749 - 2¹⁵ = 7781889416981 is a prime.

It is a super-2 number, since 2×7781889449749² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7781889449729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3890944724874 + 3890944724875.

It is an arithmetic number, because the mean of its divisors is an integer number (3890944724875).

Almost surely, 2^{7781889449749} is an apocalyptic number.

It is an amenable number.

7781889449749 is a deficient number, since it is larger than the sum of its proper divisors (1).

7781889449749 is an equidigital number, since it uses as much as digits as its factorization.

7781889449749 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8193540096, while the sum is 85.

The spelling of 7781889449749 in words is "seven trillion, seven hundred eighty-one billion, eight hundred eighty-nine million, four hundred forty-nine thousand, seven hundred forty-nine".