823813409 has 6 divisors (see below), whose sum is σ = 825602274. Its totient is φ = 822027360.

The previous prime is 823813391. The next prime is 823813439. The reversal of 823813409 is 904318328.

It can be written as a sum of positive squares in only one way, i.e., 584430625 + 239382784 = 24175^2 + 15472^2 .

It is not a de Polignac number, because 823813409 - 2¹² = 823809313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (823813439) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 851444 + ... + 852410.

It is an arithmetic number, because the mean of its divisors is an integer number (137600379).

Almost surely, 2^823813409 is an apocalyptic number.

It is an amenable number.

823813409 is a deficient number, since it is larger than the sum of its proper divisors (1788865).

823813409 is an frugal number, since it uses more digits than its factorization.

823813409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2815 (or 1848 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 38.

The square root of 823813409 is about 28702.1499020544. The cubic root of 823813409 is about 937.4388592779.

The spelling of 823813409 in words is "eight hundred twenty-three million, eight hundred thirteen thousand, four hundred nine".