6819721405434 has 144 divisors (see below), whose sum is σ = 17362311749640. Its totient is φ = 1928819692800.

The previous prime is 6819721405421. The next prime is 6819721405481. The reversal of 6819721405434 is 4345041279186.

6819721405434 is a `hidden beast` number, since 6 + 8 + 1 + 97 + 2 + 1 + 4 + 0 + 543 + 4 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 6434821523025 + 384899882409 = 2536695^2 + 620403^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 105046384 + ... + 105111284.

It is a 1-persistent number, because it is pandigital, but 2⋅6819721405434 = 13639442810868 is not.

Almost surely, 2^{6819721405434} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6819721405434, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (8681155874820).

6819721405434 is an abundant number, since it is smaller than the sum of its proper divisors (10542590344206).

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

6819721405434 is a wasteful number, since it uses less digits than its factorization.

6819721405434 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66125 (or 66115 counting only the distinct ones).

The product of its (nonzero) digits is 5806080, while the sum is 54.

The spelling of 6819721405434 in words is "six trillion, eight hundred nineteen billion, seven hundred twenty-one million, four hundred five thousand, four hundred thirty-four".