125815 has 4 divisors (see below), whose sum is σ = 150984. Its totient is φ = 100648.

The previous prime is 125813. The next prime is 125821. The reversal of 125815 is 518521.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 125815 - 2¹ = 125813 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (125813) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12577 + ... + 12586.

It is an arithmetic number, because the mean of its divisors is an integer number (37746).

2¹²⁵⁸¹⁵ is an apocalyptic number.

125815 is a deficient number, since it is larger than the sum of its proper divisors (25169).

125815 is an equidigital number, since it uses as much as digits as its factorization.

125815 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25168.

The product of its digits is 400, while the sum is 22.

The square root of 125815 is about 354.7041020344. The cubic root of 125815 is about 50.1084313495.

The spelling of 125815 in words is "one hundred twenty-five thousand, eight hundred fifteen".