28156891 has 8 divisors (see below), whose sum is σ = 32283360. Its totient is φ = 24056448.

The previous prime is 28156871. The next prime is 28156927. The reversal of 28156891 is 19865182.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 28156891 - 2⁵ = 28156859 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28156871) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4126 + ... + 8563.

It is an arithmetic number, because the mean of its divisors is an integer number (4035420).

Almost surely, 2^28156891 is an apocalyptic number.

28156891 is a deficient number, since it is larger than the sum of its proper divisors (4126469).

28156891 is a wasteful number, since it uses less digits than its factorization.

28156891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13013.

The product of its digits is 34560, while the sum is 40.

The square root of 28156891 is about 5306.3067193671. The cubic root of 28156891 is about 304.2250000670.

The spelling of 28156891 in words is "twenty-eight million, one hundred fifty-six thousand, eight hundred ninety-one".