28777820 has 12 divisors (see below), whose sum is σ = 60433464. Its totient is φ = 11511120.

The previous prime is 28777817. The next prime is 28777877. The reversal of 28777820 is 2877782.

It is a hoax number, since the sum of its digits (41) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 719426 + ... + 719465.

It is an arithmetic number, because the mean of its divisors is an integer number (5036122).

Almost surely, 2^28777820 is an apocalyptic number.

28777820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28777820 is an abundant number, since it is smaller than the sum of its proper divisors (31655644).

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

28777820 is a wasteful number, since it uses less digits than its factorization.

28777820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1438900 (or 1438898 counting only the distinct ones).

The product of its (nonzero) digits is 87808, while the sum is 41.

The square root of 28777820 is about 5364.4962484841. The cubic root of 28777820 is about 306.4450641224.

The spelling of 28777820 in words is "twenty-eight million, seven hundred seventy-seven thousand, eight hundred twenty".