28155531 has 8 divisors (see below), whose sum is σ = 37641280. Its totient is φ = 18720072.

The previous prime is 28155529. The next prime is 28155539. The reversal of 28155531 is 13555182.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 28155531 - 2¹ = 28155529 is a prime.

It is a super-2 number, since 2×28155531² = 1585467851783922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28155539) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11245 + ... + 13518.

It is an arithmetic number, because the mean of its divisors is an integer number (4705160).

Almost surely, 2^28155531 is an apocalyptic number.

28155531 is a deficient number, since it is larger than the sum of its proper divisors (9485749).

28155531 is a wasteful number, since it uses less digits than its factorization.

28155531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25145.

The product of its digits is 6000, while the sum is 30.

The square root of 28155531 is about 5306.1785684238. The cubic root of 28155531 is about 304.2201018858.

The spelling of 28155531 in words is "twenty-eight million, one hundred fifty-five thousand, five hundred thirty-one".