228651781 has 4 divisors (see below), whose sum is σ = 228751552. Its totient is φ = 228552012.

The previous prime is 228651733. The next prime is 228651799. The reversal of 228651781 is 187156822.

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: 187156822 = 2 ⋅93578411.

It is a cyclic number.

It is not a de Polignac number, because 228651781 - 2⁷ = 228651653 is a prime.

It is a super-2 number, since 2×228651781² = 104563273908943922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (228651881) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 46365 + ... + 51058.

It is an arithmetic number, because the mean of its divisors is an integer number (57187888).

Almost surely, 2^228651781 is an apocalyptic number.

It is an amenable number.

228651781 is a deficient number, since it is larger than the sum of its proper divisors (99771).

228651781 is an equidigital number, since it uses as much as digits as its factorization.

228651781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99770.

The product of its digits is 53760, while the sum is 40.

The square root of 228651781 is about 15121.2360936532. The cubic root of 228651781 is about 611.4930558156.

The spelling of 228651781 in words is "two hundred twenty-eight million, six hundred fifty-one thousand, seven hundred eighty-one".