809947800841 has 3 divisors (see below), whose sum is σ = 809948700813. Its totient is φ = 809946900870.

The previous prime is 809947800817. The next prime is 809947800881. The reversal of 809947800841 is 148008749908.

The square root of 809947800841 is 899971.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 809947800841 - 2¹³ = 809947792649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (809947800881) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 449986 + ... + 1349956.

It is an arithmetic number, because the mean of its divisors is an integer number (269982900271).

Almost surely, 2^809947800841 is an apocalyptic number.

809947800841 is the 899971-st square number.

809947800841 is the 449986-th centered octagonal number.

It is an amenable number.

809947800841 is a deficient number, since it is larger than the sum of its proper divisors (899972).

809947800841 is an frugal number, since it uses more digits than its factorization.

809947800841 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1799942 (or 899971 counting only the distinct ones).

The product of its (nonzero) digits is 4644864, while the sum is 58.

The spelling of 809947800841 in words is "eight hundred nine billion, nine hundred forty-seven million, eight hundred thousand, eight hundred forty-one".