28156557 has 16 divisors (see below), whose sum is σ = 44106048. Its totient is φ = 15751680.

The previous prime is 28156547. The next prime is 28156559. The reversal of 28156557 is 75565182.

It is not a de Polignac number, because 28156557 - 2⁶ = 28156493 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28156559) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32388 + ... + 33245.

It is an arithmetic number, because the mean of its divisors is an integer number (2756628).

Almost surely, 2^28156557 is an apocalyptic number.

It is an amenable number.

28156557 is a deficient number, since it is larger than the sum of its proper divisors (15949491).

28156557 is a wasteful number, since it uses less digits than its factorization.

28156557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65660.

The product of its digits is 84000, while the sum is 39.

The square root of 28156557 is about 5306.2752472898. The cubic root of 28156557 is about 304.2237971460.

The spelling of 28156557 in words is "twenty-eight million, one hundred fifty-six thousand, five hundred fifty-seven".