21438609648 has 40 divisors (see below), whose sum is σ = 55393515600. Its totient is φ = 7144856064.

The previous prime is 21438609641. The next prime is 21438609659. The reversal of 21438609648 is 84690683412.

It is a super-2 number, since 2×21438609648² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21438609648.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21438609641) 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, 233818 + ... + 312326.

It is an arithmetic number, because the mean of its divisors is an integer number (1384837890).

Almost surely, 2^21438609648 is an apocalyptic number.

It is an amenable number.

21438609648 is an abundant number, since it is smaller than the sum of its proper divisors (33954905952).

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

21438609648 is a wasteful number, since it uses less digits than its factorization.

21438609648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84209 (or 84203 counting only the distinct ones).

The product of its (nonzero) digits is 1990656, while the sum is 51.

The spelling of 21438609648 in words is "twenty-one billion, four hundred thirty-eight million, six hundred nine thousand, six hundred forty-eight".