28904820 has 48 divisors (see below), whose sum is σ = 92496768. Its totient is φ = 6606720.

The previous prime is 28904809. The next prime is 28904831. The reversal of 28904820 is 2840982.

It is an interprime number because it is at equal distance from previous prime (28904809) and next prime (28904831).

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, 33991 + ... + 34830.

It is an arithmetic number, because the mean of its divisors is an integer number (1927016).

Almost surely, 2^28904820 is an apocalyptic number.

28904820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28904820 is an abundant number, since it is smaller than the sum of its proper divisors (63591948).

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

28904820 is a wasteful number, since it uses less digits than its factorization.

28904820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68840 (or 68838 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 33.

The square root of 28904820 is about 5376.3203029581. The cubic root of 28904820 is about 306.8951956517.

The spelling of 28904820 in words is "twenty-eight million, nine hundred four thousand, eight hundred twenty".