28299381 has 16 divisors (see below), whose sum is σ = 41532480. Its totient is φ = 16997120.

The previous prime is 28299377. The next prime is 28299391. The reversal of 28299381 is 18399282.

It is a cyclic number.

It is not a de Polignac number, because 28299381 - 2² = 28299377 is a prime.

It is a super-2 number, since 2×28299381² = 1601709929966322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28299371) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 66 + ... + 7523.

It is an arithmetic number, because the mean of its divisors is an integer number (2595780).

Almost surely, 2^28299381 is an apocalyptic number.

It is an amenable number.

28299381 is a deficient number, since it is larger than the sum of its proper divisors (13233099).

28299381 is a wasteful number, since it uses less digits than its factorization.

28299381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7716.

The product of its digits is 62208, while the sum is 42.

The square root of 28299381 is about 5319.7162518315. The cubic root of 28299381 is about 304.7373210891.

Subtracting from 28299381 its reverse (18399282), we obtain a palindrome (9900099).

It can be divided in two parts, 28299 and 381, that added together give a triangular number (28680 = T₂₃₉).

The spelling of 28299381 in words is "twenty-eight million, two hundred ninety-nine thousand, three hundred eighty-one".