1028780820 has 36 divisors (see below), whose sum is σ = 3120635700. Its totient is φ = 274341504.

The previous prime is 1028780807. The next prime is 1028780843. The reversal of 1028780820 is 280878201.

It can be written as a sum of positive squares in 2 ways, for example, as 669981456 + 358799364 = 25884^2 + 18942^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2857545 + ... + 2857904.

It is an arithmetic number, because the mean of its divisors is an integer number (86684325).

Almost surely, 2^1028780820 is an apocalyptic number.

1028780820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1028780820 is an abundant number, since it is smaller than the sum of its proper divisors (2091854880).

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

1028780820 is a wasteful number, since it uses less digits than its factorization.

1028780820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5715464 (or 5715459 counting only the distinct ones).

The product of its (nonzero) digits is 14336, while the sum is 36.

The square root of 1028780820 is about 32074.6133258064. The cubic root of 1028780820 is about 1009.5030133404.

The spelling of 1028780820 in words is "one billion, twenty-eight million, seven hundred eighty thousand, eight hundred twenty".