1028645681 has 16 divisors (see below), whose sum is σ = 1201238400. Its totient is φ = 880482960.

The previous prime is 1028645669. The next prime is 1028645729. The reversal of 1028645681 is 1865468201.

It is not a de Polignac number, because 1028645681 - 2¹⁰ = 1028644657 is a prime.

It is a super-2 number, since 2×1028645681² = 2116223874079907522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1028645381) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 321170 + ... + 324356.

It is an arithmetic number, because the mean of its divisors is an integer number (75077400).

Almost surely, 2^1028645681 is an apocalyptic number.

It is an amenable number.

1028645681 is a deficient number, since it is larger than the sum of its proper divisors (172592719).

1028645681 is an frugal number, since it uses more digits than its factorization.

1028645681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4149 (or 4135 counting only the distinct ones).

The product of its (nonzero) digits is 92160, while the sum is 41.

The square root of 1028645681 is about 32072.5066217157. The cubic root of 1028645681 is about 1009.4588091721.

The spelling of 1028645681 in words is "one billion, twenty-eight million, six hundred forty-five thousand, six hundred eighty-one".