28129866 has 16 divisors (see below), whose sum is σ = 59569344. Its totient is φ = 8825024.

The previous prime is 28129853. The next prime is 28129867. The reversal of 28129866 is 66892182.

It is a super-2 number, since 2×28129866² = 1582578722355912, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (28129867) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 137790 + ... + 137993.

It is an arithmetic number, because the mean of its divisors is an integer number (3723084).

Almost surely, 2^28129866 is an apocalyptic number.

28129866 is an abundant number, since it is smaller than the sum of its proper divisors (31439478).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

28129866 is a wasteful number, since it uses less digits than its factorization.

28129866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 275805.

The product of its digits is 82944, while the sum is 42.

The square root of 28129866 is about 5303.7596099371. The cubic root of 28129866 is about 304.1276371347.

The spelling of 28129866 in words is "twenty-eight million, one hundred twenty-nine thousand, eight hundred sixty-six".