21025357056 has 576 divisors, whose sum is σ = 71229312000. Its totient is φ = 6061547520.

The previous prime is 21025357051. The next prime is 21025357109. The reversal of 21025357056 is 65075352012.

21025357056 is a `hidden beast` number, since 2 + 1 + 0 + 2 + 535 + 70 + 56 = 666.

It is a tau number, because it is divible by the number of its divisors (576).

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

It is a self number, because there is not a number n which added to its sum of digits gives 21025357056.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21025357051) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 192893130 + ... + 192893238.

It is an arithmetic number, because the mean of its divisors is an integer number (123662000).

Almost surely, 2^21025357056 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 21025357056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35614656000).

21025357056 is an abundant number, since it is smaller than the sum of its proper divisors (50203954944).

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

21025357056 is a wasteful number, since it uses less digits than its factorization.

21025357056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 247 (or 227 counting only the distinct ones).

The product of its (nonzero) digits is 63000, while the sum is 36.

The spelling of 21025357056 in words is "twenty-one billion, twenty-five million, three hundred fifty-seven thousand, fifty-six".