28397986 has 8 divisors (see below), whose sum is σ = 42763500. Its totient is φ = 14143488.

The previous prime is 28397969. The next prime is 28397987. The reversal of 28397986 is 68979382.

It can be written as a sum of positive squares in 2 ways, for example, as 23474025 + 4923961 = 4845^2 + 2219^2 .

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

It is a super-3 number, since 3×28397986³ (a number of 23 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (28397987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27111 + ... + 28138.

Almost surely, 2^28397986 is an apocalyptic number.

28397986 is a deficient number, since it is larger than the sum of its proper divisors (14365514).

28397986 is a wasteful number, since it uses less digits than its factorization.

28397986 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55508.

The product of its digits is 1306368, while the sum is 52.

The square root of 28397986 is about 5328.9760742567. The cubic root of 28397986 is about 305.0908481498.

The spelling of 28397986 in words is "twenty-eight million, three hundred ninety-seven thousand, nine hundred eighty-six".