21305404416 has 44 divisors (see below), whose sum is σ = 56786678552. Its totient is φ = 7101800448.

The previous prime is 21305404409. The next prime is 21305404429. The reversal of 21305404416 is 61440450312.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3464605 + ... + 3470748.

Almost surely, 2^21305404416 is an apocalyptic number.

It is an amenable number.

21305404416 is an abundant number, since it is smaller than the sum of its proper divisors (35481274136).

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

21305404416 is an equidigital number, since it uses as much as digits as its factorization.

21305404416 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6935376 (or 6935358 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 30.

Adding to 21305404416 its reverse (61440450312), we get a palindrome (82745854728).

The spelling of 21305404416 in words is "twenty-one billion, three hundred five million, four hundred four thousand, four hundred sixteen".