28191340 has 24 divisors (see below), whose sum is σ = 59376240. Its totient is φ = 11243328.

The previous prime is 28191337. The next prime is 28191341. The reversal of 28191340 is 4319182.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 28191299 and 28191308.

It is not an unprimeable number, because it can be changed into a prime (28191341) 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 7 ways as a sum of consecutive naturals, for example, 5571 + ... + 9349.

It is an arithmetic number, because the mean of its divisors is an integer number (2474010).

Almost surely, 2^28191340 is an apocalyptic number.

28191340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28191340 is an abundant number, since it is smaller than the sum of its proper divisors (31184900).

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

28191340 is a wasteful number, since it uses less digits than its factorization.

28191340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4161 (or 4159 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 28191340 is about 5309.5517701591. The cubic root of 28191340 is about 304.3490191553.

The spelling of 28191340 in words is "twenty-eight million, one hundred ninety-one thousand, three hundred forty".