125781 has 4 divisors (see below), whose sum is σ = 167712. Its totient is φ = 83852.

The previous prime is 125777. The next prime is 125789. The reversal of 125781 is 187521.

125781 is digitally balanced in base 7, because in such base it contains all the possibile digits an equal number of times.

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: 187521 = 3 ⋅62507.

It is a cyclic number.

It is not a de Polignac number, because 125781 - 2² = 125777 is a prime.

It is a super-2 number, since 2×125781² = 31641719922, which contains 22 as substring.

It is a D-number.

125781 is strictly pandigital in base 7.

125781 is a lucky number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 125781.

It is not an unprimeable number, because it can be changed into a prime (125789) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20961 + ... + 20966.

It is an arithmetic number, because the mean of its divisors is an integer number (41928).

2¹²⁵⁷⁸¹ is an apocalyptic number.

It is an amenable number.

125781 is a deficient number, since it is larger than the sum of its proper divisors (41931).

125781 is an equidigital number, since it uses as much as digits as its factorization.

125781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41930.

The product of its digits is 560, while the sum is 24.

The square root of 125781 is about 354.6561715239. The cubic root of 125781 is about 50.1039172080.

The spelling of 125781 in words is "one hundred twenty-five thousand, seven hundred eighty-one".