820279664640 has 448 divisors, whose sum is σ = 2952698915520. Its totient is φ = 218717356032.

The previous prime is 820279664573. The next prime is 820279664641. The reversal of 820279664640 is 46466972028.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (820279664641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 89574942 + ... + 89584098.

Almost surely, 2^820279664640 is an apocalyptic number.

820279664640 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 820279664640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1476349457760).

820279664640 is an abundant number, since it is smaller than the sum of its proper divisors (2132419250880).

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

820279664640 is an frugal number, since it uses more digits than its factorization.

820279664640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9209 (or 9167 counting only the distinct ones).

The product of its (nonzero) digits is 6967296, while the sum is 54.

The spelling of 820279664640 in words is "eight hundred twenty billion, two hundred seventy-nine million, six hundred sixty-four thousand, six hundred forty".