28072861 has 4 divisors (see below), whose sum is σ = 29550400. Its totient is φ = 26595324.

The previous prime is 28072859. The next prime is 28072873. The reversal of 28072861 is 16827082.

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 28072861 - 2¹ = 28072859 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 (28072061) 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, 738741 + ... + 738778.

It is an arithmetic number, because the mean of its divisors is an integer number (7387600).

Almost surely, 2^28072861 is an apocalyptic number.

It is an amenable number.

28072861 is a deficient number, since it is larger than the sum of its proper divisors (1477539).

28072861 is a wasteful number, since it uses less digits than its factorization.

28072861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1477538.

The product of its (nonzero) digits is 10752, while the sum is 34.

The square root of 28072861 is about 5298.3828664980. The cubic root of 28072861 is about 303.9220606117.

The spelling of 28072861 in words is "twenty-eight million, seventy-two thousand, eight hundred sixty-one".