21415739648 has 72 divisors (see below), whose sum is σ = 45568118400. Its totient is φ = 10015709184.

The previous prime is 21415739623. The next prime is 21415739659. The reversal of 21415739648 is 84693751412.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21415739596 and 21415739605.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 356390 + ... + 412122.

Almost surely, 2^21415739648 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 21415739648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22784059200).

21415739648 is an abundant number, since it is smaller than the sum of its proper divisors (24152378752).

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

21415739648 is an equidigital number, since it uses as much as digits as its factorization.

21415739648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55847 (or 55833 counting only the distinct ones).

The product of its digits is 1451520, while the sum is 50.

The spelling of 21415739648 in words is "twenty-one billion, four hundred fifteen million, seven hundred thirty-nine thousand, six hundred forty-eight".