28145869 has 4 divisors (see below), whose sum is σ = 28255644. Its totient is φ = 28036096.

The previous prime is 28145849. The next prime is 28145879. The reversal of 28145869 is 96854182.

It is a happy number.

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 15507844 + 12638025 = 3938^2 + 3555^2 .

It is a cyclic number.

It is not a de Polignac number, because 28145869 - 2²¹ = 26048717 is a prime.

It is a super-2 number, since 2×28145869² = 1584379883530322, 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 (28145839) 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, 54502 + ... + 55015.

It is an arithmetic number, because the mean of its divisors is an integer number (7063911).

Almost surely, 2^28145869 is an apocalyptic number.

It is an amenable number.

28145869 is a deficient number, since it is larger than the sum of its proper divisors (109775).

28145869 is a wasteful number, since it uses less digits than its factorization.

28145869 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109774.

The product of its digits is 138240, while the sum is 43.

The square root of 28145869 is about 5305.2680422388. The cubic root of 28145869 is about 304.1852986481.

The spelling of 28145869 in words is "twenty-eight million, one hundred forty-five thousand, eight hundred sixty-nine".