818221680 has 120 divisors (see below), whose sum is σ = 2755069200. Its totient is φ = 217620480.

The previous prime is 818221661. The next prime is 818221699. The reversal of 818221680 is 86122818.

It is an interprime number because it is at equal distance from previous prime (818221661) and next prime (818221699).

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (36).

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 23 ways as a sum of consecutive naturals, for example, 322015 + ... + 324545.

It is an arithmetic number, because the mean of its divisors is an integer number (22958910).

Almost surely, 2^818221680 is an apocalyptic number.

818221680 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 818221680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1377534600).

818221680 is an abundant number, since it is smaller than the sum of its proper divisors (1936847520).

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

818221680 is a wasteful number, since it uses less digits than its factorization.

818221680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2999 (or 2990 counting only the distinct ones).

The product of its (nonzero) digits is 12288, while the sum is 36.

The square root of 818221680 is about 28604.5744593413. The cubic root of 818221680 is about 935.3130506362.

The spelling of 818221680 in words is "eight hundred eighteen million, two hundred twenty-one thousand, six hundred eighty".