807813821 has 8 divisors (see below), whose sum is σ = 836041080. Its totient is φ = 779611392.

The previous prime is 807813817. The next prime is 807813829. The reversal of 807813821 is 128318708.

It can be written as a sum of positive squares in 4 ways, for example, as 315595225 + 492218596 = 17765^2 + 22186^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 807813821 - 2² = 807813817 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 (807813829) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 80921 + ... + 90353.

It is an arithmetic number, because the mean of its divisors is an integer number (104505135).

Almost surely, 2^807813821 is an apocalyptic number.

It is an amenable number.

807813821 is a deficient number, since it is larger than the sum of its proper divisors (28227259).

807813821 is a wasteful number, since it uses less digits than its factorization.

807813821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12415.

The product of its (nonzero) digits is 21504, while the sum is 38.

The square root of 807813821 is about 28422.0657412511. The cubic root of 807813821 is about 931.3303583284.

The spelling of 807813821 in words is "eight hundred seven million, eight hundred thirteen thousand, eight hundred twenty-one".