1028509861 has 2 divisors, whose sum is σ = 1028509862. Its totient is φ = 1028509860.

The previous prime is 1028509849. The next prime is 1028509871. The reversal of 1028509861 is 1689058201.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 876752100 + 151757761 = 29610^2 + 12319^2 .

It is an emirp because it is prime and its reverse (1689058201) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1028509861 - 2⁵ = 1028509829 is a prime.

It is a super-3 number, since 3×1028509861³ (a number of 28 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1028509871) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 514254930 + 514254931.

It is an arithmetic number, because the mean of its divisors is an integer number (514254931).

Almost surely, 2^1028509861 is an apocalyptic number.

It is an amenable number.

1028509861 is a deficient number, since it is larger than the sum of its proper divisors (1).

1028509861 is an equidigital number, since it uses as much as digits as its factorization.

1028509861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34560, while the sum is 40.

The square root of 1028509861 is about 32070.3891619668. The cubic root of 1028509861 is about 1009.4143783466.

The spelling of 1028509861 in words is "one billion, twenty-eight million, five hundred nine thousand, eight hundred sixty-one".