820937819888640 has 880 divisors, whose sum is σ = 2990616771729312. Its totient is φ = 215293077356544.

The previous prime is 820937819888639. The next prime is 820937819888663. The reversal of 820937819888640 is 46888918739028.

820937819888640 is a `hidden beast` number, since 8 + 20 + 9 + 378 + 1 + 98 + 88 + 64 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (81).

It is a self number, because there is not a number n which added to its sum of digits gives 820937819888640.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 17032941022 + ... + 17032989218.

Almost surely, 2^{820937819888640} is an apocalyptic number.

820937819888640 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 820937819888640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1495308385864656).

820937819888640 is an abundant number, since it is smaller than the sum of its proper divisors (2169678951840672).

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

820937819888640 is a wasteful number, since it uses less digits than its factorization.

820937819888640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48914 (or 48887 counting only the distinct ones).

The product of its (nonzero) digits is 2675441664, while the sum is 81.

The spelling of 820937819888640 in words is "eight hundred twenty trillion, nine hundred thirty-seven billion, eight hundred nineteen million, eight hundred eighty-eight thousand, six hundred forty".