28404981 has 24 divisors (see below), whose sum is σ = 47118240. Its totient is φ = 16308000.

The previous prime is 28404919. The next prime is 28404989. The reversal of 28404981 is 18940482.

It is not a de Polignac number, because 28404981 - 2⁷ = 28404853 is a prime.

It is a super-2 number, since 2×28404981² = 1613685891220722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28404989) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5670 + ... + 9431.

It is an arithmetic number, because the mean of its divisors is an integer number (1963260).

Almost surely, 2^28404981 is an apocalyptic number.

It is an amenable number.

28404981 is a deficient number, since it is larger than the sum of its proper divisors (18713259).

28404981 is a wasteful number, since it uses less digits than its factorization.

28404981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15137 (or 15134 counting only the distinct ones).

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

The square root of 28404981 is about 5329.6323512978. The cubic root of 28404981 is about 305.1158961148.

The spelling of 28404981 in words is "twenty-eight million, four hundred four thousand, nine hundred eighty-one".