228639681 has 12 divisors (see below), whose sum is σ = 349684452. Its totient is φ = 143460096.

The previous prime is 228639661. The next prime is 228639689. The reversal of 228639681 is 186936822.

228639681 is a `hidden beast` number, since 2 + 2 + 8 + 639 + 6 + 8 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 179989056 + 48650625 = 13416^2 + 6975^2 .

It is not a de Polignac number, because 228639681 - 2¹³ = 228631489 is a prime.

It is a super-2 number, since 2×228639681² = 104552207455563522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (228639689) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 747036 + ... + 747341.

It is an arithmetic number, because the mean of its divisors is an integer number (29140371).

Almost surely, 2^228639681 is an apocalyptic number.

It is an amenable number.

228639681 is a deficient number, since it is larger than the sum of its proper divisors (121044771).

228639681 is a wasteful number, since it uses less digits than its factorization.

228639681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1494400 (or 1494397 counting only the distinct ones).

The product of its digits is 248832, while the sum is 45.

The square root of 228639681 is about 15120.8359887937. The cubic root of 228639681 is about 611.4822691127.

The spelling of 228639681 in words is "two hundred twenty-eight million, six hundred thirty-nine thousand, six hundred eighty-one".