63645437856 has 384 divisors, whose sum is σ = 225701683200. Its totient is φ = 15255751680.

The previous prime is 63645437851. The next prime is 63645437857. The reversal of 63645437856 is 65873454636.

It is a junction number, because it is equal to n+sod(n) for n = 63645437796 and 63645437805.

It is not an unprimeable number, because it can be changed into a prime (63645437851) 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, 16238265 + ... + 16242183.

It is an arithmetic number, because the mean of its divisors is an integer number (587764800).

Almost surely, 2^63645437856 is an apocalyptic number.

63645437856 is a gapful number since it is divisible by the number (66) 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 63645437856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (112850841600).

63645437856 is an abundant number, since it is smaller than the sum of its proper divisors (162056245344).

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

63645437856 is a wasteful number, since it uses less digits than its factorization.

63645437856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3989 (or 3955 counting only the distinct ones).

The product of its digits is 43545600, while the sum is 57.

It can be divided in two parts, 63645 and 437856, that added together give a triangular number (501501 = T₁₀₀₁).

The spelling of 63645437856 in words is "sixty-three billion, six hundred forty-five million, four hundred thirty-seven thousand, eight hundred fifty-six".