21208428184321 has 8 divisors (see below), whose sum is σ = 24238246489920. Its totient is φ = 18178620591408.

The previous prime is 21208428184219. The next prime is 21208428184337. The reversal of 21208428184321 is 12348182480212.

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 21208428184321 - 2⁷ = 21208428184193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21208428184621) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2142675 + ... + 6856231.

It is an arithmetic number, because the mean of its divisors is an integer number (3029780811240).

Almost surely, 2^{21208428184321} is an apocalyptic number.

It is an amenable number.

21208428184321 is a deficient number, since it is larger than the sum of its proper divisors (3029818305599).

21208428184321 is an equidigital number, since it uses as much as digits as its factorization.

21208428184321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5356343.

The product of its (nonzero) digits is 393216, while the sum is 46.

The spelling of 21208428184321 in words is "twenty-one trillion, two hundred eight billion, four hundred twenty-eight million, one hundred eighty-four thousand, three hundred twenty-one".