1028905865 has 32 divisors (see below), whose sum is σ = 1368765216. Its totient is φ = 737648640.

The previous prime is 1028905859. The next prime is 1028905883. The reversal of 1028905865 is 5685098201.

It can be written as a sum of positive squares in 16 ways, for example, as 888814969 + 140090896 = 29813^2 + 11836^2 .

It is not a de Polignac number, because 1028905865 - 2¹⁰ = 1028904841 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 620117 + ... + 621773.

It is an arithmetic number, because the mean of its divisors is an integer number (42773913).

Almost surely, 2^1028905865 is an apocalyptic number.

It is an amenable number.

1028905865 is a deficient number, since it is larger than the sum of its proper divisors (339859351).

1028905865 is a wasteful number, since it uses less digits than its factorization.

1028905865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1949.

The product of its (nonzero) digits is 172800, while the sum is 44.

The square root of 1028905865 is about 32076.5625496249. The cubic root of 1028905865 is about 1009.5439122983.

The spelling of 1028905865 in words is "one billion, twenty-eight million, nine hundred five thousand, eight hundred sixty-five".