809495620518821 has 16 divisors (see below), whose sum is σ = 811478564409600. Its totient is φ = 807513727899648.

The previous prime is 809495620518791. The next prime is 809495620518833. The reversal of 809495620518821 is 128815026594908.

It is a cyclic number.

It is not a de Polignac number, because 809495620518821 - 2⁶ = 809495620518757 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (809495620518421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 29620375685 + ... + 29620403013.

It is an arithmetic number, because the mean of its divisors is an integer number (50717410275600).

Almost surely, 2^{809495620518821} is an apocalyptic number.

It is an amenable number.

809495620518821 is a deficient number, since it is larger than the sum of its proper divisors (1982943890779).

809495620518821 is a wasteful number, since it uses less digits than its factorization.

809495620518821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43948.

The product of its (nonzero) digits is 99532800, while the sum is 68.

The spelling of 809495620518821 in words is "eight hundred nine trillion, four hundred ninety-five billion, six hundred twenty million, five hundred eighteen thousand, eight hundred twenty-one".