16643421527821 has 8 divisors (see below), whose sum is σ = 18156490905600. Its totient is φ = 15130357326240.

The previous prime is 16643421527813. The next prime is 16643421527833. The reversal of 16643421527821 is 12872512434661.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 16643421527821 - 2³ = 16643421527813 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16643421567821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8965785 + ... + 10661713.

It is an arithmetic number, because the mean of its divisors is an integer number (2269561363200).

Almost surely, 2^{16643421527821} is an apocalyptic number.

16643421527821 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

16643421527821 is a deficient number, since it is larger than the sum of its proper divisors (1513069377779).

16643421527821 is a wasteful number, since it uses less digits than its factorization.

16643421527821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2588099.

The product of its digits is 3870720, while the sum is 52.

The spelling of 16643421527821 in words is "sixteen trillion, six hundred forty-three billion, four hundred twenty-one million, five hundred twenty-seven thousand, eight hundred twenty-one".