28681551 has 12 divisors (see below), whose sum is σ = 42857880. Its totient is φ = 18461520.

The previous prime is 28681531. The next prime is 28681577. The reversal of 28681551 is 15518682.

28681551 is a `hidden beast` number, since 28 + 6 + 81 + 551 = 666.

It is not a de Polignac number, because 28681551 - 2¹⁹ = 28157263 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28681511) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 54685 + ... + 55206.

It is an arithmetic number, because the mean of its divisors is an integer number (3571490).

Almost surely, 2^28681551 is an apocalyptic number.

28681551 is a deficient number, since it is larger than the sum of its proper divisors (14176329).

28681551 is a wasteful number, since it uses less digits than its factorization.

28681551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109926 (or 109923 counting only the distinct ones).

The product of its digits is 19200, while the sum is 36.

The square root of 28681551 is about 5355.5159415317. The cubic root of 28681551 is about 306.1029706004.

The spelling of 28681551 in words is "twenty-eight million, six hundred eighty-one thousand, five hundred fifty-one".