125021209 has 4 divisors (see below), whose sum is σ = 125050420. Its totient is φ = 124992000.

The previous prime is 125021207. The next prime is 125021231. The reversal of 125021209 is 902120521.

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

It can be written as a sum of positive squares in 2 ways, for example, as 87235600 + 37785609 = 9340^2 + 6147^2 .

It is a cyclic number.

It is not a de Polignac number, because 125021209 - 2¹ = 125021207 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 125021209.

It is not an unprimeable number, because it can be changed into a prime (125021201) 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, 6792 + ... + 17209.

It is an arithmetic number, because the mean of its divisors is an integer number (31262605).

Almost surely, 2^125021209 is an apocalyptic number.

It is an amenable number.

125021209 is a deficient number, since it is larger than the sum of its proper divisors (29211).

125021209 is an equidigital number, since it uses as much as digits as its factorization.

125021209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29210.

The product of its (nonzero) digits is 360, while the sum is 22.

The square root of 125021209 is about 11181.2883425838. The cubic root of 125021209 is about 500.0282770675.

The spelling of 125021209 in words is "one hundred twenty-five million, twenty-one thousand, two hundred nine".