809159921 has 4 divisors (see below), whose sum is σ = 810255600. Its totient is φ = 808064244.

The previous prime is 809159917. The next prime is 809159933. The reversal of 809159921 is 129951908.

It is a happy number.

809159921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 809159921 - 2² = 809159917 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (809159951) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 546731 + ... + 548208.

It is an arithmetic number, because the mean of its divisors is an integer number (202563900).

Almost surely, 2^809159921 is an apocalyptic number.

It is an amenable number.

809159921 is a deficient number, since it is larger than the sum of its proper divisors (1095679).

809159921 is a wasteful number, since it uses less digits than its factorization.

809159921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1095678.

The product of its (nonzero) digits is 58320, while the sum is 44.

The square root of 809159921 is about 28445.7364292085. The cubic root of 809159921 is about 931.8473784881.

The spelling of 809159921 in words is "eight hundred nine million, one hundred fifty-nine thousand, nine hundred twenty-one".