1028820642665 has 16 divisors (see below), whose sum is σ = 1283774086800. Its totient is φ = 790557745152.

The previous prime is 1028820642643. The next prime is 1028820642671. The reversal of 1028820642665 is 5662460288201.

It can be written as a sum of positive squares in 8 ways, for example, as 21613704256 + 1007206938409 = 147016^2 + 1003597^2 .

It is a cyclic number.

It is not a de Polignac number, because 1028820642665 - 2¹² = 1028820638569 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18353660 + ... + 18409629.

It is an arithmetic number, because the mean of its divisors is an integer number (80235880425).

Almost surely, 2^{1028820642665} is an apocalyptic number.

It is an amenable number.

1028820642665 is a deficient number, since it is larger than the sum of its proper divisors (254953444135).

1028820642665 is a wasteful number, since it uses less digits than its factorization.

1028820642665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36763516.

The product of its (nonzero) digits is 2211840, while the sum is 50.

The spelling of 1028820642665 in words is "one trillion, twenty-eight billion, eight hundred twenty million, six hundred forty-two thousand, six hundred sixty-five".