21840616646064 has 280 divisors, whose sum is σ = 64197967762032. Its totient is φ = 7194220830720.

The previous prime is 21840616646039. The next prime is 21840616646081. The reversal of 21840616646064 is 46064661604812.

21840616646064 is a `hidden beast` number, since 2 + 1 + 8 + 4 + 0 + 61 + 66 + 460 + 64 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a self number, because there is not a number n which added to its sum of digits gives 21840616646064.

It is an unprimeable number.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 444152199 + ... + 444201369.

Almost surely, 2^{21840616646064} is an apocalyptic number.

21840616646064 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21840616646064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32098983881016).

21840616646064 is an abundant number, since it is smaller than the sum of its proper divisors (42357351115968).

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

21840616646064 is a wasteful number, since it uses less digits than its factorization.

21840616646064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49647 (or 49626 counting only the distinct ones).

The product of its (nonzero) digits is 7962624, while the sum is 54.

The spelling of 21840616646064 in words is "twenty-one trillion, eight hundred forty billion, six hundred sixteen million, six hundred forty-six thousand, sixty-four".