28544981 has 4 divisors (see below), whose sum is σ = 28555692. Its totient is φ = 28534272.

The previous prime is 28544963. The next prime is 28544983. The reversal of 28544981 is 18944582.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 13256881 + 15288100 = 3641^2 + 3910^2 .

It is a cyclic number.

It is not a de Polignac number, because 28544981 - 2⁶ = 28544917 is a prime.

It is a super-2 number, since 2×28544981² = 1629631880580722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28544983) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2135 + ... + 7851.

It is an arithmetic number, because the mean of its divisors is an integer number (7138923).

Almost surely, 2^28544981 is an apocalyptic number.

It is an amenable number.

28544981 is a deficient number, since it is larger than the sum of its proper divisors (10711).

28544981 is an equidigital number, since it uses as much as digits as its factorization.

28544981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10710.

The product of its digits is 92160, while the sum is 41.

The square root of 28544981 is about 5342.7503216976. The cubic root of 28544981 is about 305.6163510446.

The spelling of 28544981 in words is "twenty-eight million, five hundred forty-four thousand, nine hundred eighty-one".