823979520 has 640 divisors, whose sum is σ = 3629767680. Its totient is φ = 172523520.

The previous prime is 823979483. The next prime is 823979567. The reversal of 823979520 is 25979328.

It is a tau number, because it is divible by the number of its divisors (640).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 6289855 + ... + 6289985.

It is an arithmetic number, because the mean of its divisors is an integer number (5671512).

Almost surely, 2^823979520 is an apocalyptic number.

823979520 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 823979520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1814883840).

823979520 is an abundant number, since it is smaller than the sum of its proper divisors (2805788160).

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

823979520 is a wasteful number, since it uses less digits than its factorization.

823979520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 183 (or 161 counting only the distinct ones).

The product of its (nonzero) digits is 272160, while the sum is 45.

The square root of 823979520 is about 28705.0434592947. The cubic root of 823979520 is about 937.5018623963.

The spelling of 823979520 in words is "eight hundred twenty-three million, nine hundred seventy-nine thousand, five hundred twenty".