28156986 has 48 divisors (see below), whose sum is σ = 71678880. Its totient is φ = 7875360.

The previous prime is 28156969. The next prime is 28157027. The reversal of 28156986 is 68965182.

28156986 is a `hidden beast` number, since 2 + 8 + 1 + 569 + 86 = 666.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 2896 + ... + 8043.

It is an arithmetic number, because the mean of its divisors is an integer number (1493310).

Almost surely, 2^28156986 is an apocalyptic number.

28156986 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

28156986 is an abundant number, since it is smaller than the sum of its proper divisors (43521894).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

28156986 is a wasteful number, since it uses less digits than its factorization.

28156986 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10971 (or 10968 counting only the distinct ones).

The product of its digits is 207360, while the sum is 45.

The square root of 28156986 is about 5306.3156709717. The cubic root of 28156986 is about 304.2253422135.

It can be divided in two parts, 2815 and 6986, that added together give a square (9801 = 99²).

The spelling of 28156986 in words is "twenty-eight million, one hundred fifty-six thousand, nine hundred eighty-six".