21242464056 has 512 divisors, whose sum is σ = 71774208000. Its totient is φ = 5748019200.

The previous prime is 21242464051. The next prime is 21242464091. The reversal of 21242464056 is 65046424212.

21242464056 is a `hidden beast` number, since 2 + 1 + 2 + 4 + 2 + 4 + 640 + 5 + 6 = 666.

It is a super-2 number, since 2×21242464056² (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 21242464056.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21242464051) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 60176776 + ... + 60177128.

It is an arithmetic number, because the mean of its divisors is an integer number (140184000).

Almost surely, 2^21242464056 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 21242464056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35887104000).

21242464056 is an abundant number, since it is smaller than the sum of its proper divisors (50531743944).

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

21242464056 is a wasteful number, since it uses less digits than its factorization.

21242464056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 472 (or 462 counting only the distinct ones).

The product of its (nonzero) digits is 92160, while the sum is 36.

Adding to 21242464056 its reverse (65046424212), we get a palindrome (86288888268).

The spelling of 21242464056 in words is "twenty-one billion, two hundred forty-two million, four hundred sixty-four thousand, fifty-six".