28197988 has 72 divisors (see below), whose sum is σ = 62717760. Its totient is φ = 10857600.

The previous prime is 28197971. The next prime is 28198007. The reversal of 28197988 is 88979182.

It is a Harshad number since it is a multiple of its sum of digits (52).

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 279138 + ... + 279238.

It is an arithmetic number, because the mean of its divisors is an integer number (871080).

Almost surely, 2^28197988 is an apocalyptic number.

28197988 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28197988, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31358880).

28197988 is an abundant number, since it is smaller than the sum of its proper divisors (34519772).

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

28197988 is a wasteful number, since it uses less digits than its factorization.

28197988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 197 (or 182 counting only the distinct ones).

The product of its digits is 580608, while the sum is 52.

The square root of 28197988 is about 5310.1777748019. The cubic root of 28197988 is about 304.3729408426.

The spelling of 28197988 in words is "twenty-eight million, one hundred ninety-seven thousand, nine hundred eighty-eight".