126688781 has 2 divisors, whose sum is σ = 126688782. Its totient is φ = 126688780.

The previous prime is 126688711. The next prime is 126688823. The reversal of 126688781 is 187886621.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 80910025 + 45778756 = 8995^2 + 6766^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-126688781 is a prime.

It is a super-2 number, since 2×126688781² = 32100094462531922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (126688711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 63344390 + 63344391.

It is an arithmetic number, because the mean of its divisors is an integer number (63344391).

Almost surely, 2^126688781 is an apocalyptic number.

It is an amenable number.

126688781 is a deficient number, since it is larger than the sum of its proper divisors (1).

126688781 is an equidigital number, since it uses as much as digits as its factorization.

126688781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 258048, while the sum is 47.

The square root of 126688781 is about 11255.6110895855. The cubic root of 126688781 is about 502.2416430539.

The spelling of 126688781 in words is "one hundred twenty-six million, six hundred eighty-eight thousand, seven hundred eighty-one".