428365809 has 9 divisors (see below), whose sum is σ = 618840313.
Its totient is φ = 285535812.
The previous prime is 428365789. The next prime is 428365831. The reversal of 428365809 is 908563824.
The square root of 428365809 is 20697.
It is a perfect power (a square), and thus also a powerful number.
It is a tau number, because it is divible by the number of its divisors (9).
It is not a de Polignac number, because 428365809 - 27 = 428365681 is a prime.
It is a Duffinian number.
It is not an unprimeable number, because it can be changed into a prime (428365859) by changing a digit.
It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 58642 + ... + 65540.
Almost surely, 2428365809 is an apocalyptic number.
428365809 is the 20697-th square number.
428365809 is the 10349-th centered octagonal number.
It is an amenable number.
428365809 is a deficient number, since it is larger than the sum of its proper divisors (190474504).
428365809 is an frugal number, since it uses more digits than its factorization.
428365809 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 13804 (or 6902 counting only the distinct ones).
The product of its (nonzero) digits is 414720, while the sum is 45.
The cubic root of 428365809 is about 753.8268457909.
The spelling of 428365809 in words is "four hundred twenty-eight million, three hundred sixty-five thousand, eight hundred nine".