28231998 has 16 divisors (see below), whose sum is σ = 56681856. Its totient is φ = 9374360.

The previous prime is 28231969. The next prime is 28232003. The reversal of 28231998 is 89913282.

It is a super-2 number, since 2×28231998² = 1594091422144008, which contains 22 as substring.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7368 + ... + 10523.

It is an arithmetic number, because the mean of its divisors is an integer number (3542616).

Almost surely, 2^28231998 is an apocalyptic number.

28231998 is an abundant number, since it is smaller than the sum of its proper divisors (28449858).

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

28231998 is a wasteful number, since it uses less digits than its factorization.

28231998 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18159.

The product of its digits is 62208, while the sum is 42.

The square root of 28231998 is about 5313.3791507853. The cubic root of 28231998 is about 304.4952612095.

The spelling of 28231998 in words is "twenty-eight million, two hundred thirty-one thousand, nine hundred ninety-eight".