681447779 has 2 divisors, whose sum is σ = 681447780. Its totient is φ = 681447778.

The previous prime is 681447763. The next prime is 681447803. The reversal of 681447779 is 977744186.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 681447779 - 2⁴ = 681447763 is a prime.

It is a super-3 number, since 3×681447779³ (a number of 27 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 681447779.

It is not a weakly prime, because it can be changed into another prime (681447709) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340723889 + 340723890.

It is an arithmetic number, because the mean of its divisors is an integer number (340723890).

Almost surely, 2^681447779 is an apocalyptic number.

681447779 is a deficient number, since it is larger than the sum of its proper divisors (1).

681447779 is an equidigital number, since it uses as much as digits as its factorization.

681447779 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2370816, while the sum is 53.

The square root of 681447779 is about 26104.5547558276. The cubic root of 681447779 is about 879.9895741706.

The spelling of 681447779 in words is "six hundred eighty-one million, four hundred forty-seven thousand, seven hundred seventy-nine".