21909229927424 has 132 divisors (see below), whose sum is σ = 51038164092744. Its totient is φ = 9372979961856.

The previous prime is 21909229927369. The next prime is 21909229927477. The reversal of 21909229927424 is 42472992290912.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 27861302 + ... + 28636874.

Almost surely, 2^{21909229927424} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21909229927424, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25519082046372).

21909229927424 is an abundant number, since it is smaller than the sum of its proper divisors (29128934165320).

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

21909229927424 is an equidigital number, since it uses as much as digits as its factorization.

21909229927424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 776170 (or 776145 counting only the distinct ones).

The product of its (nonzero) digits is 23514624, while the sum is 62.

The spelling of 21909229927424 in words is "twenty-one trillion, nine hundred nine billion, two hundred twenty-nine million, nine hundred twenty-seven thousand, four hundred twenty-four".