28281121 has 4 divisors (see below), whose sum is σ = 30852144. Its totient is φ = 25710100.

The previous prime is 28281091. The next prime is 28281151. The reversal of 28281121 is 12118282.

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 an interprime number because it is at equal distance from previous prime (28281091) and next prime (28281151).

It is a cyclic number.

It is not a de Polignac number, because 28281121 - 2¹³ = 28272929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28281151) 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, 1285495 + ... + 1285516.

It is an arithmetic number, because the mean of its divisors is an integer number (7713036).

Almost surely, 2^28281121 is an apocalyptic number.

It is an amenable number.

28281121 is a deficient number, since it is larger than the sum of its proper divisors (2571023).

28281121 is a wasteful number, since it uses less digits than its factorization.

28281121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2571022.

The product of its digits is 512, while the sum is 25.

The square root of 28281121 is about 5317.9997179391. Note that the first 3 decimals coincide. The cubic root of 28281121 is about 304.6717636983.

The spelling of 28281121 in words is "twenty-eight million, two hundred eighty-one thousand, one hundred twenty-one".