126840781 has 2 divisors, whose sum is σ = 126840782. Its totient is φ = 126840780.

The previous prime is 126840767. The next prime is 126840811. The reversal of 126840781 is 187048621.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 74046025 + 52794756 = 8605^2 + 7266^2 .

It is an emirp because it is prime and its reverse (187048621) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 126840781 - 2¹⁵ = 126808013 is a prime.

It is a super-2 number, since 2×126840781² = 32177167449379922, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 126840781.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (126840761) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 63420390 + 63420391.

It is an arithmetic number, because the mean of its divisors is an integer number (63420391).

Almost surely, 2^126840781 is an apocalyptic number.

It is an amenable number.

126840781 is a deficient number, since it is larger than the sum of its proper divisors (1).

126840781 is an equidigital number, since it uses as much as digits as its factorization.

126840781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 21504, while the sum is 37.

The square root of 126840781 is about 11262.3612533074. The cubic root of 126840781 is about 502.4424243663.

The spelling of 126840781 in words is "one hundred twenty-six million, eight hundred forty thousand, seven hundred eighty-one".