28420340 has 48 divisors (see below), whose sum is σ = 64668240. Its totient is φ = 10429440.

The previous prime is 28420309. The next prime is 28420363. The reversal of 28420340 is 4302482.

It can be written as a sum of positive squares in 8 ways, for example, as 2735716 + 25684624 = 1654^2 + 5068^2 .

It is a congruent number.

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 15 ways as a sum of consecutive naturals, for example, 72866 + ... + 73254.

It is an arithmetic number, because the mean of its divisors is an integer number (1347255).

Almost surely, 2^28420340 is an apocalyptic number.

28420340 is a gapful number since it is divisible by the number (20) 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 28420340, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32334120).

28420340 is an abundant number, since it is smaller than the sum of its proper divisors (36247900).

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

28420340 is a wasteful number, since it uses less digits than its factorization.

28420340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 692 (or 690 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 23.

The square root of 28420340 is about 5331.0730627145. The cubic root of 28420340 is about 305.1708797889.

The spelling of 28420340 in words is "twenty-eight million, four hundred twenty thousand, three hundred forty".