25216209 has 6 divisors (see below), whose sum is σ = 36423426. Its totient is φ = 16810800.

The previous prime is 25216201. The next prime is 25216223. The reversal of 25216209 is 90261252.

It can be written as a sum of positive squares in only one way, i.e., 20793600 + 4422609 = 4560^2 + 2103^2 .

It is not a de Polignac number, because 25216209 - 2³ = 25216201 is a prime.

It is not an unprimeable number, because it can be changed into a prime (25216201) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1400892 + ... + 1400909.

It is an arithmetic number, because the mean of its divisors is an integer number (6070571).

Almost surely, 2^25216209 is an apocalyptic number.

It is an amenable number.

25216209 is a deficient number, since it is larger than the sum of its proper divisors (11207217).

25216209 is a wasteful number, since it uses less digits than its factorization.

25216209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2801807 (or 2801804 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 25216209 is about 5021.5743547218. The cubic root of 25216209 is about 293.2422873716.

It can be divided in two parts, 25216 and 209, that added together give a triangular number (25425 = T₂₂₅).

The spelling of 25216209 in words is "twenty-five million, two hundred sixteen thousand, two hundred nine".