28912869 has 28 divisors (see below), whose sum is σ = 45919116. Its totient is φ = 18133632.

The previous prime is 28912867. The next prime is 28912883. The reversal of 28912869 is 96821982.

It can be written as a sum of positive squares in 2 ways, for example, as 16402500 + 12510369 = 4050^2 + 3537^2 .

It is not a de Polignac number, because 28912869 - 2¹ = 28912867 is a prime.

It is a super-2 number, since 2×28912869² = 1671907987622322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28912861) by changing a digit.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 11227 + ... + 13559.

Almost surely, 2^28912869 is an apocalyptic number.

It is an amenable number.

28912869 is a deficient number, since it is larger than the sum of its proper divisors (17006247).

28912869 is an equidigital number, since it uses as much as digits as its factorization.

28912869 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2368 (or 2353 counting only the distinct ones).

The product of its digits is 124416, while the sum is 45.

The square root of 28912869 is about 5377.0688111647. The cubic root of 28912869 is about 306.9236795998.

The spelling of 28912869 in words is "twenty-eight million, nine hundred twelve thousand, eight hundred sixty-nine".