125638813 has 4 divisors (see below), whose sum is σ = 125665020. Its totient is φ = 125612608.

The previous prime is 125638783. The next prime is 125638841. The reversal of 125638813 is 318836521.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 318836521 = 3491 ⋅91331.

It can be written as a sum of positive squares in 2 ways, for example, as 97357689 + 28281124 = 9867^2 + 5318^2 .

It is a cyclic number.

It is not a de Polignac number, because 125638813 - 2⁵ = 125638781 is a prime.

It is a super-2 number, since 2×125638813² = 31570222664097938, 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 (125638853) 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, 3628 + ... + 16261.

It is an arithmetic number, because the mean of its divisors is an integer number (31416255).

Almost surely, 2^125638813 is an apocalyptic number.

It is an amenable number.

125638813 is a deficient number, since it is larger than the sum of its proper divisors (26207).

125638813 is an equidigital number, since it uses as much as digits as its factorization.

125638813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26206.

The product of its digits is 34560, while the sum is 37.

The square root of 125638813 is about 11208.8720663589. The cubic root of 125638813 is about 500.8503038138.

The spelling of 125638813 in words is "one hundred twenty-five million, six hundred thirty-eight thousand, eight hundred thirteen".