823207840 has 288 divisors, whose sum is σ = 2508471504. Its totient is φ = 252887040.

The previous prime is 823207831. The next prime is 823207859. The reversal of 823207840 is 48702328.

It can be written as a sum of positive squares in 8 ways, for example, as 231161616 + 592046224 = 15204^2 + 24332^2 .

It is a super-2 number, since 2×823207840² = 1355342295674931200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 823207796 and 823207805.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 4178622 + ... + 4178818.

Almost surely, 2^823207840 is an apocalyptic number.

823207840 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 823207840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1254235752).

823207840 is an abundant number, since it is smaller than the sum of its proper divisors (1685263664).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

823207840 is a wasteful number, since it uses less digits than its factorization.

823207840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 280 (or 265 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 34.

The square root of 823207840 is about 28691.5987703718. The cubic root of 823207840 is about 937.2091053631.

The spelling of 823207840 in words is "eight hundred twenty-three million, two hundred seven thousand, eight hundred forty".