21208496736 has 384 divisors, whose sum is σ = 68124672000. Its totient is φ = 5767856640.

The previous prime is 21208496723. The next prime is 21208496759. The reversal of 21208496736 is 63769480212.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 80640541 + ... + 80640803.

It is an arithmetic number, because the mean of its divisors is an integer number (177408000).

Almost surely, 2^21208496736 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 21208496736, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34062336000).

21208496736 is an abundant number, since it is smaller than the sum of its proper divisors (46916175264).

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

21208496736 is a wasteful number, since it uses less digits than its factorization.

21208496736 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 407 (or 385 counting only the distinct ones).

The product of its (nonzero) digits is 870912, while the sum is 48.

The spelling of 21208496736 in words is "twenty-one billion, two hundred eight million, four hundred ninety-six thousand, seven hundred thirty-six".