1166668781 has 2 divisors, whose sum is σ = 1166668782. Its totient is φ = 1166668780.

The previous prime is 1166668771. The next prime is 1166668801. The reversal of 1166668781 is 1878666611.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1165607881 + 1060900 = 34141^2 + 1030^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1166668781 is a prime.

It is a super-2 number, since 2×1166668781² = 2722232089120051922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1166668771) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 583334390 + 583334391.

It is an arithmetic number, because the mean of its divisors is an integer number (583334391).

Almost surely, 2^1166668781 is an apocalyptic number.

It is an amenable number.

1166668781 is a deficient number, since it is larger than the sum of its proper divisors (1).

1166668781 is an equidigital number, since it uses as much as digits as its factorization.

1166668781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 580608, while the sum is 50.

The square root of 1166668781 is about 34156.5335038555. The cubic root of 1166668781 is about 1052.7272355561.

The spelling of 1166668781 in words is "one billion, one hundred sixty-six million, six hundred sixty-eight thousand, seven hundred eighty-one".