809546921 has 4 divisors (see below), whose sum is σ = 822818244. Its totient is φ = 796275600.

The previous prime is 809546873. The next prime is 809546929. The reversal of 809546921 is 129645908.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 340218025 + 469328896 = 18445^2 + 21664^2 .

It is a cyclic number.

It is not a de Polignac number, because 809546921 - 2¹⁰ = 809545897 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (809546929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6635570 + ... + 6635691.

It is an arithmetic number, because the mean of its divisors is an integer number (205704561).

Almost surely, 2^809546921 is an apocalyptic number.

It is an amenable number.

809546921 is a deficient number, since it is larger than the sum of its proper divisors (13271323).

809546921 is a wasteful number, since it uses less digits than its factorization.

809546921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13271322.

The product of its (nonzero) digits is 155520, while the sum is 44.

The square root of 809546921 is about 28452.5380414472. The cubic root of 809546921 is about 931.9959142096.

The spelling of 809546921 in words is "eight hundred nine million, five hundred forty-six thousand, nine hundred twenty-one".