810145806561 has 225 divisors, whose sum is σ = 1538593224201. Its totient is φ = 424607811264.

The previous prime is 810145806541. The next prime is 810145806593. The reversal of 810145806561 is 165608541018.

The square root of 810145806561 is 900081.

It is a perfect power (a square), and thus also a powerful number.

810145806561 is a `hidden beast` number, since 8 + 1 + 0 + 1 + 4 + 5 + 80 + 6 + 561 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 261242632161 + 548903174400 = 511119^2 + 740880^2 .

It is not a de Polignac number, because 810145806561 - 2⁷ = 810145806433 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (810145806541) by changing a digit.

It is a polite number, since it can be written in 224 ways as a sum of consecutive naturals, for example, 5160164295 + ... + 5160164451.

Almost surely, 2^810145806561 is an apocalyptic number.

810145806561 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

810145806561 is the 900081-st square number.

810145806561 is the 450041-st centered octagonal number.

It is an amenable number.

810145806561 is a deficient number, since it is larger than the sum of its proper divisors (728447417640).

810145806561 is an frugal number, since it uses more digits than its factorization.

810145806561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 380 (or 180 counting only the distinct ones).

The product of its (nonzero) digits is 230400, while the sum is 45.

The spelling of 810145806561 in words is "eight hundred ten billion, one hundred forty-five million, eight hundred six thousand, five hundred sixty-one".