63643644 has 72 divisors (see below), whose sum is σ = 171011568. Its totient is φ = 20684160.

The previous prime is 63643627. The next prime is 63643649. The reversal of 63643644 is 44634636.

63643644 is a `hidden beast` number, since 6 + 3 + 6 + 4 + 3 + 644 = 666.

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

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 63643599 and 63643608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (63643649) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 39054 + ... + 40650.

Almost surely, 2^63643644 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 63643644, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (85505784).

63643644 is an abundant number, since it is smaller than the sum of its proper divisors (107367924).

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

63643644 is a wasteful number, since it uses less digits than its factorization.

63643644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1657 (or 1643 counting only the distinct ones).

The product of its digits is 124416, while the sum is 36.

The square root of 63643644 is about 7977.6966600642. The cubic root of 63643644 is about 399.2562094630.

It can be divided in two parts, 6 and 3643644, that added together give a triangular number (3643650 = T₂₆₉₉).

The spelling of 63643644 in words is "sixty-three million, six hundred forty-three thousand, six hundred forty-four".