21285053856 has 384 divisors, whose sum is σ = 69417492480. Its totient is φ = 6343729920.

The previous prime is 21285053831. The next prime is 21285053887. The reversal of 21285053856 is 65835058212.

21285053856 is a `hidden beast` number, since 2 + 12 + 8 + 50 + 538 + 56 = 666.

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, 95448561 + ... + 95448783.

It is an arithmetic number, because the mean of its divisors is an integer number (180774720).

Almost surely, 2^21285053856 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 21285053856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34708746240).

21285053856 is an abundant number, since it is smaller than the sum of its proper divisors (48132438624).

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

21285053856 is a wasteful number, since it uses less digits than its factorization.

21285053856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 358 (or 322 counting only the distinct ones).

The product of its (nonzero) digits is 576000, while the sum is 45.

The spelling of 21285053856 in words is "twenty-one billion, two hundred eighty-five million, fifty-three thousand, eight hundred fifty-six".