28776820 has 24 divisors (see below), whose sum is σ = 60787944. Its totient is φ = 11442816.

The previous prime is 28776799. The next prime is 28776821. The reversal of 28776820 is 2867782.

It can be written as a sum of positive squares in 4 ways, for example, as 17338896 + 11437924 = 4164^2 + 3382^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28776821) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 699 + ... + 7618.

It is an arithmetic number, because the mean of its divisors is an integer number (2532831).

Almost surely, 2^28776820 is an apocalyptic number.

28776820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28776820 is an abundant number, since it is smaller than the sum of its proper divisors (32011124).

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

28776820 is a wasteful number, since it uses less digits than its factorization.

28776820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8499 (or 8497 counting only the distinct ones).

The product of its (nonzero) digits is 75264, while the sum is 40.

The square root of 28776820 is about 5364.4030422779. The cubic root of 28776820 is about 306.4415145298.

The spelling of 28776820 in words is "twenty-eight million, seven hundred seventy-six thousand, eight hundred twenty".