642568428 has 72 divisors (see below), whose sum is σ = 1688821680. Its totient is φ = 205752960.

The previous prime is 642568373. The next prime is 642568439. The reversal of 642568428 is 824865246.

642568428 is a `hidden beast` number, since 6 + 42 + 568 + 42 + 8 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 218826 + ... + 221742.

Almost surely, 2^642568428 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 642568428, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (844410840).

642568428 is an abundant number, since it is smaller than the sum of its proper divisors (1046253252).

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

642568428 is a wasteful number, since it uses less digits than its factorization.

642568428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3167 (or 3162 counting only the distinct ones).

The product of its digits is 737280, while the sum is 45.

The square root of 642568428 is about 25348.9334686886. The cubic root of 642568428 is about 862.9251519582.

The spelling of 642568428 in words is "six hundred forty-two million, five hundred sixty-eight thousand, four hundred twenty-eight".