28015861 has 4 divisors (see below), whose sum is σ = 29490400. Its totient is φ = 26541324.

The previous prime is 28015843. The next prime is 28015907. The reversal of 28015861 is 16851082.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 28015861 - 2⁹ = 28015349 is a prime.

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 pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 737241 + ... + 737278.

It is an arithmetic number, because the mean of its divisors is an integer number (7372600).

Almost surely, 2^28015861 is an apocalyptic number.

It is an amenable number.

28015861 is a deficient number, since it is larger than the sum of its proper divisors (1474539).

28015861 is a wasteful number, since it uses less digits than its factorization.

28015861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1474538.

The product of its (nonzero) digits is 3840, while the sum is 31.

The square root of 28015861 is about 5293.0011335725. The cubic root of 28015861 is about 303.7162236712.

The spelling of 28015861 in words is "twenty-eight million, fifteen thousand, eight hundred sixty-one".