125372809 has 3 divisors (see below), whose sum is σ = 125384007. Its totient is φ = 125361612.

The previous prime is 125372801. The next prime is 125372813. The reversal of 125372809 is 908273521.

The square root of 125372809 is 11197.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 908273521 = 37 ⋅24547933.

It can be written as a sum of positive squares in only one way, i.e., 28783225 + 96589584 = 5365^2 + 9828^2 .

It is not a de Polignac number, because 125372809 - 2³ = 125372801 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (125372801) 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 2 ways as a sum of consecutive naturals, for example, 5599 + ... + 16795.

It is an arithmetic number, because the mean of its divisors is an integer number (41794669).

Almost surely, 2^125372809 is an apocalyptic number.

125372809 is the 11197-th square number.

125372809 is the 5599-th centered octagonal number.

It is an amenable number.

125372809 is a deficient number, since it is larger than the sum of its proper divisors (11198).

125372809 is an frugal number, since it uses more digits than its factorization.

125372809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22394 (or 11197 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 37.

The cubic root of 125372809 is about 500.4965853095.

The spelling of 125372809 in words is "one hundred twenty-five million, three hundred seventy-two thousand, eight hundred nine".