642544128 has 240 divisors, whose sum is σ = 2010808800. Its totient is φ = 196853760.

The previous prime is 642544081. The next prime is 642544129. The reversal of 642544128 is 821445246.

642544128 is a `hidden beast` number, since 642 + 5 + 4 + 4 + 1 + 2 + 8 = 666.

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

It is a junction number, because it is equal to n+sod(n) for n = 642544092 and 642544101.

It is not an unprimeable number, because it can be changed into a prime (642544129) 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, 3589543 + ... + 3589721.

It is an arithmetic number, because the mean of its divisors is an integer number (8378370).

Almost surely, 2^642544128 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 642544128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1005404400).

642544128 is an abundant number, since it is smaller than the sum of its proper divisors (1368264672).

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

642544128 is a wasteful number, since it uses less digits than its factorization.

642544128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 263 (or 244 counting only the distinct ones).

The product of its digits is 61440, while the sum is 36.

The square root of 642544128 is about 25348.4541540505. The cubic root of 642544128 is about 862.9142740788.

The spelling of 642544128 in words is "six hundred forty-two million, five hundred forty-four thousand, one hundred twenty-eight".