809977950921 has 4 divisors (see below), whose sum is σ = 1079970601232. Its totient is φ = 539985300612.

The previous prime is 809977950893. The next prime is 809977950941. The reversal of 809977950921 is 129059779908.

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 not a de Polignac number, because 809977950921 - 2¹¹ = 809977948873 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (809977950941) 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, 134996325151 + ... + 134996325156.

It is an arithmetic number, because the mean of its divisors is an integer number (269992650308).

Almost surely, 2^809977950921 is an apocalyptic number.

It is an amenable number.

809977950921 is a deficient number, since it is larger than the sum of its proper divisors (269992650311).

809977950921 is a wasteful number, since it uses less digits than its factorization.

809977950921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 269992650310.

The product of its (nonzero) digits is 25719120, while the sum is 66.

The spelling of 809977950921 in words is "eight hundred nine billion, nine hundred seventy-seven million, nine hundred fifty thousand, nine hundred twenty-one".