21085403472 has 240 divisors, whose sum is σ = 68830233472. Its totient is φ = 5901050880.

The previous prime is 21085403459. The next prime is 21085403497. The reversal of 21085403472 is 27430458012.

It is a happy number.

21085403472 is a `hidden beast` number, since 2 + 10 + 8 + 540 + 34 + 72 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 18876258 + ... + 18877374.

Almost surely, 2^21085403472 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 21085403472, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34415116736).

21085403472 is an abundant number, since it is smaller than the sum of its proper divisors (47744830000).

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

21085403472 is a wasteful number, since it uses less digits than its factorization.

21085403472 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1506 (or 1497 counting only the distinct ones).

The product of its (nonzero) digits is 53760, while the sum is 36.

The spelling of 21085403472 in words is "twenty-one billion, eighty-five million, four hundred three thousand, four hundred seventy-two".