28801891 has 8 divisors (see below), whose sum is σ = 30521600. Its totient is φ = 27102600.

The previous prime is 28801889. The next prime is 28801907. The reversal of 28801891 is 19810882.

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 28801891 - 2¹ = 28801889 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28801891.

It is not an unprimeable number, because it can be changed into a prime (28801831) 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 7 ways as a sum of consecutive naturals, for example, 2151 + ... + 7888.

It is an arithmetic number, because the mean of its divisors is an integer number (3815200).

Almost surely, 2^28801891 is an apocalyptic number.

28801891 is the 2869-th nonagonal number.

28801891 is a deficient number, since it is larger than the sum of its proper divisors (1719709).

28801891 is a wasteful number, since it uses less digits than its factorization.

28801891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10209.

The product of its (nonzero) digits is 9216, while the sum is 37.

The square root of 28801891 is about 5366.7393266303. The cubic root of 28801891 is about 306.5304815659.

It can be divided in two parts, 28801 and 891, that added together give a palindrome (29692).

The spelling of 28801891 in words is "twenty-eight million, eight hundred one thousand, eight hundred ninety-one".