228157309 has 4 divisors (see below), whose sum is σ = 238077216. Its totient is φ = 218237404.

The previous prime is 228157291. The next prime is 228157327. The reversal of 228157309 is 903751822.

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: 903751822 = 2 ⋅451875911.

It is an interprime number because it is at equal distance from previous prime (228157291) and next prime (228157327).

It is a cyclic number.

It is not a de Polignac number, because 228157309 - 2¹¹ = 228155261 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 (228157379) 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, 4959919 + ... + 4959964.

It is an arithmetic number, because the mean of its divisors is an integer number (59519304).

Almost surely, 2^228157309 is an apocalyptic number.

It is an amenable number.

228157309 is a deficient number, since it is larger than the sum of its proper divisors (9919907).

228157309 is an equidigital number, since it uses as much as digits as its factorization.

228157309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9919906.

The product of its (nonzero) digits is 30240, while the sum is 37.

The square root of 228157309 is about 15104.8769938719. The cubic root of 228157309 is about 611.0519419432.

The spelling of 228157309 in words is "two hundred twenty-eight million, one hundred fifty-seven thousand, three hundred nine".