63721728 has 180 divisors, whose sum is σ = 217645120. Its totient is φ = 18164736.

The previous prime is 63721681. The next prime is 63721739. The reversal of 63721728 is 82712736.

63721728 is a `hidden beast` number, since 637 + 2 + 17 + 2 + 8 = 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 = 63721692 and 63721701.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 144933 + ... + 145371.

Almost surely, 2^63721728 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 63721728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (108822560).

63721728 is an abundant number, since it is smaller than the sum of its proper divisors (153923392).

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

63721728 is an equidigital number, since it uses as much as digits as its factorization.

63721728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 474 (or 451 counting only the distinct ones).

The product of its digits is 28224, while the sum is 36.

The square root of 63721728 is about 7982.5890536843. The cubic root of 63721728 is about 399.4194244043.

It can be divided in two parts, 6372 and 1728, that added together give a square (8100 = 90²).

The spelling of 63721728 in words is "sixty-three million, seven hundred twenty-one thousand, seven hundred twenty-eight".