28657638 has 20 divisors (see below), whose sum is σ = 64214700. Its totient is φ = 9552492.

The previous prime is 28657637. The next prime is 28657661. The reversal of 28657638 is 83675682.

28657638 is a `hidden beast` number, since 2 + 8 + 6 + 5 + 7 + 638 = 666.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 28657593 and 28657602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28657633) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 88288 + ... + 88611.

It is an arithmetic number, because the mean of its divisors is an integer number (3210735).

Almost surely, 2^28657638 is an apocalyptic number.

28657638 is an abundant number, since it is smaller than the sum of its proper divisors (35557062).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

28657638 is a wasteful number, since it uses less digits than its factorization.

28657638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 176913 (or 176904 counting only the distinct ones).

The product of its digits is 483840, while the sum is 45.

The square root of 28657638 is about 5353.2829179859. The cubic root of 28657638 is about 306.0178766949.

The spelling of 28657638 in words is "twenty-eight million, six hundred fifty-seven thousand, six hundred thirty-eight".