21688407385409 has 8 divisors (see below), whose sum is σ = 21989088264192. Its totient is φ = 21387823247520.

The previous prime is 21688407385369. The next prime is 21688407385441. The reversal of 21688407385409 is 90458370488612.

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 21688407385409 - 2³² = 21684112418113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21688407385499) 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, 23733677 + ... + 24630554.

It is an arithmetic number, because the mean of its divisors is an integer number (2748636033024).

It is a 1-persistent number, because it is pandigital, but 2⋅21688407385409 = 43376814770818 is not.

Almost surely, 2^{21688407385409} is an apocalyptic number.

It is an amenable number.

21688407385409 is a deficient number, since it is larger than the sum of its proper divisors (300680878783).

21688407385409 is an equidigital number, since it uses as much as digits as its factorization.

21688407385409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48370447.

The product of its (nonzero) digits is 92897280, while the sum is 65.

The spelling of 21688407385409 in words is "twenty-one trillion, six hundred eighty-eight billion, four hundred seven million, three hundred eighty-five thousand, four hundred nine".