21036544056 has 144 divisors (see below), whose sum is σ = 66308533200. Its totient is φ = 5999685120.

The previous prime is 21036543953. The next prime is 21036544057. The reversal of 21036544056 is 65044563012.

21036544056 is a `hidden beast` number, since 2 + 103 + 6 + 544 + 0 + 5 + 6 = 666.

It is a super-2 number, since 2×21036544056² (a number of 21 digits) contains 22 as substring.

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 21036544056.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21036544057) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 77085 + ... + 219123.

It is an arithmetic number, because the mean of its divisors is an integer number (460475925).

Almost surely, 2^21036544056 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 21036544056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33154266600).

21036544056 is an abundant number, since it is smaller than the sum of its proper divisors (45271989144).

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

21036544056 is a wasteful number, since it uses less digits than its factorization.

21036544056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 142090 (or 142072 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 36.

The spelling of 21036544056 in words is "twenty-one billion, thirty-six million, five hundred forty-four thousand, fifty-six".