28821138 has 16 divisors (see below), whose sum is σ = 60676320. Its totient is φ = 9101376.

The previous prime is 28821131. The next prime is 28821161. The reversal of 28821138 is 83112882.

It is a junction number, because it is equal to n+sod(n) for n = 28821099 and 28821108.

It is not an unprimeable number, because it can be changed into a prime (28821131) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 126295 + ... + 126522.

It is an arithmetic number, because the mean of its divisors is an integer number (3792270).

Almost surely, 2^28821138 is an apocalyptic number.

28821138 is an abundant number, since it is smaller than the sum of its proper divisors (31855182).

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

28821138 is a wasteful number, since it uses less digits than its factorization.

28821138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 252841.

The product of its digits is 6144, while the sum is 33.

The square root of 28821138 is about 5368.5322016358. The cubic root of 28821138 is about 306.5987465104.

The spelling of 28821138 in words is "twenty-eight million, eight hundred twenty-one thousand, one hundred thirty-eight".