126786781 has 4 divisors (see below), whose sum is σ = 138312864. Its totient is φ = 115260700.

The previous prime is 126786773. The next prime is 126786817. The reversal of 126786781 is 187687621.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 187687621 = 11 ⋅17062511.

It is a cyclic number.

It is not a de Polignac number, because 126786781 - 2³ = 126786773 is a prime.

It is a super-2 number, since 2×126786781² = 32149775672683922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (126786721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5763025 + ... + 5763046.

It is an arithmetic number, because the mean of its divisors is an integer number (34578216).

Almost surely, 2^126786781 is an apocalyptic number.

126786781 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

126786781 is a deficient number, since it is larger than the sum of its proper divisors (11526083).

126786781 is a wasteful number, since it uses less digits than its factorization.

126786781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11526082.

The product of its digits is 225792, while the sum is 46.

The square root of 126786781 is about 11259.9636322681. The cubic root of 126786781 is about 502.3711125429.

The spelling of 126786781 in words is "one hundred twenty-six million, seven hundred eighty-six thousand, seven hundred eighty-one".