28981224 has 24 divisors (see below), whose sum is σ = 78491010. Its totient is φ = 9660384.

The previous prime is 28981207. The next prime is 28981241. The reversal of 28981224 is 42218982.

It is an interprime number because it is at equal distance from previous prime (28981207) and next prime (28981241).

It can be written as a sum of positive squares in only one way, i.e., 17489124 + 11492100 = 4182^2 + 3390^2 .

It is a tau number, because it is divible by the number of its divisors (24).

It is a super-2 number, since 2×28981224² = 1679822689076352, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 201187 + ... + 201330.

Almost surely, 2^28981224 is an apocalyptic number.

28981224 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

28981224 is an abundant number, since it is smaller than the sum of its proper divisors (49509786).

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

28981224 is a wasteful number, since it uses less digits than its factorization.

28981224 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 402529 (or 402522 counting only the distinct ones).

The product of its digits is 18432, while the sum is 36.

The square root of 28981224 is about 5383.4212170329. The cubic root of 28981224 is about 307.1653627126.

The spelling of 28981224 in words is "twenty-eight million, nine hundred eighty-one thousand, two hundred twenty-four".