228997309 has 4 divisors (see below), whose sum is σ = 231358204. Its totient is φ = 226636416.

The previous prime is 228997283. The next prime is 228997319. The reversal of 228997309 is 903799822.

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 83722500 + 145274809 = 9150^2 + 12053^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-228997309 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (228997319) 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, 1180302 + ... + 1180495.

It is an arithmetic number, because the mean of its divisors is an integer number (57839551).

Almost surely, 2^228997309 is an apocalyptic number.

It is an amenable number.

228997309 is a deficient number, since it is larger than the sum of its proper divisors (2360895).

228997309 is an equidigital number, since it uses as much as digits as its factorization.

228997309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2360894.

The product of its (nonzero) digits is 489888, while the sum is 49.

The square root of 228997309 is about 15132.6570370177. The cubic root of 228997309 is about 611.8009208020.

The spelling of 228997309 in words is "two hundred twenty-eight million, nine hundred ninety-seven thousand, three hundred nine".