821339768340 has 1920 divisors, whose sum is σ = 3619463823360. Its totient is φ = 150816079872.

The previous prime is 821339768309. The next prime is 821339768351. The reversal of 821339768340 is 43867933128.

821339768340 is a `hidden beast` number, since 8 + 213 + 397 + 6 + 8 + 34 + 0 = 666.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 639 ways as a sum of consecutive naturals, for example, 2237982837 + ... + 2237983203.

It is an arithmetic number, because the mean of its divisors is an integer number (1885137408).

Almost surely, 2^821339768340 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 821339768340, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1809731911680).

821339768340 is an abundant number, since it is smaller than the sum of its proper divisors (2798124055020).

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

821339768340 is a wasteful number, since it uses less digits than its factorization.

821339768340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 491 (or 480 counting only the distinct ones).

The product of its (nonzero) digits is 5225472, while the sum is 54.

The spelling of 821339768340 in words is "eight hundred twenty-one billion, three hundred thirty-nine million, seven hundred sixty-eight thousand, three hundred forty".