28013869 has 4 divisors (see below), whose sum is σ = 30168796. Its totient is φ = 25858944.

The previous prime is 28013861. The next prime is 28013873. The reversal of 28013869 is 96831082.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7628644 + 20385225 = 2762^2 + 4515^2 .

It is a cyclic number.

It is not a de Polignac number, because 28013869 - 2³ = 28013861 is a prime.

It is a super-2 number, since 2×28013869² = 1569553712698322, 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 (28013861) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1077444 + ... + 1077469.

It is an arithmetic number, because the mean of its divisors is an integer number (7542199).

Almost surely, 2^28013869 is an apocalyptic number.

It is an amenable number.

28013869 is a deficient number, since it is larger than the sum of its proper divisors (2154927).

28013869 is a wasteful number, since it uses less digits than its factorization.

28013869 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2154926.

The product of its (nonzero) digits is 20736, while the sum is 37.

The square root of 28013869 is about 5292.8129572090. The cubic root of 28013869 is about 303.7090251649.

It can be divided in two parts, 28013 and 869, that added together give a palindrome (28882).

The spelling of 28013869 in words is "twenty-eight million, thirteen thousand, eight hundred sixty-nine".