28281555 has 28 divisors (see below), whose sum is σ = 50890080. Its totient is φ = 15081552.

The previous prime is 28281553. The next prime is 28281581. The reversal of 28281555 is 55518282.

28281555 is a `hidden beast` number, since 28 + 2 + 81 + 555 = 666.

It is not a de Polignac number, because 28281555 - 2¹ = 28281553 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28281553) by changing a digit.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 235 + ... + 7524.

Almost surely, 2^28281555 is an apocalyptic number.

28281555 is a deficient number, since it is larger than the sum of its proper divisors (22608525).

28281555 is an frugal number, since it uses more digits than its factorization.

28281555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7782 (or 7767 counting only the distinct ones).

The product of its digits is 32000, while the sum is 36.

The square root of 28281555 is about 5318.0405225985. The cubic root of 28281555 is about 304.6733221805.

The spelling of 28281555 in words is "twenty-eight million, two hundred eighty-one thousand, five hundred fifty-five".