245921209 has 4 divisors (see below), whose sum is σ = 249384960. Its totient is φ = 242457460.

The previous prime is 245921183. The next prime is 245921213. The reversal of 245921209 is 902129542.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 902129542 = 2 ⋅451064771.

It is a cyclic number.

It is not a de Polignac number, because 245921209 - 2⁵ = 245921177 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (245921279) 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, 1731769 + ... + 1731910.

It is an arithmetic number, because the mean of its divisors is an integer number (62346240).

Almost surely, 2^245921209 is an apocalyptic number.

It is an amenable number.

245921209 is a deficient number, since it is larger than the sum of its proper divisors (3463751).

245921209 is an equidigital number, since it uses as much as digits as its factorization.

245921209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3463750.

The product of its (nonzero) digits is 12960, while the sum is 34.

The square root of 245921209 is about 15681.8751748635. The cubic root of 245921209 is about 626.5157526983.

The spelling of 245921209 in words is "two hundred forty-five million, nine hundred twenty-one thousand, two hundred nine".