126656781 has 4 divisors (see below), whose sum is σ = 168875712. Its totient is φ = 84437852.

The previous prime is 126656779. The next prime is 126656797. The reversal of 126656781 is 187656621.

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.

It is a cyclic number.

It is not a de Polignac number, because 126656781 - 2¹ = 126656779 is a prime.

It is a super-2 number, since 2×126656781² = 32083880346563922, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (126656771) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21109461 + ... + 21109466.

It is an arithmetic number, because the mean of its divisors is an integer number (42218928).

Almost surely, 2^126656781 is an apocalyptic number.

It is an amenable number.

126656781 is a deficient number, since it is larger than the sum of its proper divisors (42218931).

126656781 is an equidigital number, since it uses as much as digits as its factorization.

126656781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42218930.

The product of its digits is 120960, while the sum is 42.

The square root of 126656781 is about 11254.1894865868. The cubic root of 126656781 is about 502.1993528427.

The spelling of 126656781 in words is "one hundred twenty-six million, six hundred fifty-six thousand, seven hundred eighty-one".