28840420 has 36 divisors (see below), whose sum is σ = 70455420. Its totient is φ = 9887808.

The previous prime is 28840417. The next prime is 28840463. The reversal of 28840420 is 2404882.

It can be written as a sum of positive squares in 2 ways, for example, as 19695844 + 9144576 = 4438^2 + 3024^2 .

It is a Harshad number since it is a multiple of its sum of digits (28).

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 11 ways as a sum of consecutive naturals, for example, 13735 + ... + 15694.

It is an arithmetic number, because the mean of its divisors is an integer number (1957095).

Almost surely, 2^28840420 is an apocalyptic number.

28840420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28840420 is an abundant number, since it is smaller than the sum of its proper divisors (41615000).

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

28840420 is a wasteful number, since it uses less digits than its factorization.

28840420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29452 (or 29443 counting only the distinct ones).

The product of its (nonzero) digits is 4096, while the sum is 28.

The square root of 28840420 is about 5370.3277367401. The cubic root of 28840420 is about 306.6671051243.

The spelling of 28840420 in words is "twenty-eight million, eight hundred forty thousand, four hundred twenty".