28881189 has 12 divisors (see below), whose sum is σ = 41813772. Its totient is φ = 19209600.

The previous prime is 28881163. The next prime is 28881227. The reversal of 28881189 is 98118882.

It can be written as a sum of positive squares in 2 ways, for example, as 16136289 + 12744900 = 4017^2 + 3570^2 .

It is a de Polignac number, because none of the positive numbers 2^k-28881189 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28881109) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 669 + ... + 7629.

It is an arithmetic number, because the mean of its divisors is an integer number (3484481).

Almost surely, 2^28881189 is an apocalyptic number.

It is an amenable number.

28881189 is a deficient number, since it is larger than the sum of its proper divisors (12932583).

28881189 is a wasteful number, since it uses less digits than its factorization.

28881189 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7428 (or 7425 counting only the distinct ones).

The product of its digits is 73728, while the sum is 45.

The square root of 28881189 is about 5374.1221608743. The cubic root of 28881189 is about 306.8115392741.

The spelling of 28881189 in words is "twenty-eight million, eight hundred eighty-one thousand, one hundred eighty-nine".