28044381 has 4 divisors (see below), whose sum is σ = 37392512. Its totient is φ = 18696252.

The previous prime is 28044377. The next prime is 28044389. The reversal of 28044381 is 18344082.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 28044381 - 2² = 28044377 is a prime.

It is a super-2 number, since 2×28044381² = 1572974611346322, 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 (28044389) 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, 4674061 + ... + 4674066.

It is an arithmetic number, because the mean of its divisors is an integer number (9348128).

Almost surely, 2^28044381 is an apocalyptic number.

It is an amenable number.

28044381 is a deficient number, since it is larger than the sum of its proper divisors (9348131).

28044381 is an equidigital number, since it uses as much as digits as its factorization.

28044381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9348130.

The product of its (nonzero) digits is 6144, while the sum is 30.

The square root of 28044381 is about 5295.6945720085. The cubic root of 28044381 is about 303.8192492285.

The spelling of 28044381 in words is "twenty-eight million, forty-four thousand, three hundred eighty-one".