642128040 has 64 divisors (see below), whose sum is σ = 2140430400. Its totient is φ = 171233856.

The previous prime is 642128033. The next prime is 642128041. The reversal of 642128040 is 40821246.

642128040 is a `hidden beast` number, since 642 + 12 + 8 + 0 + 4 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 642127995 and 642128013.

It is not an unprimeable number, because it can be changed into a prime (642128041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 296202 + ... + 298361.

It is an arithmetic number, because the mean of its divisors is an integer number (33444225).

Almost surely, 2^642128040 is an apocalyptic number.

642128040 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

642128040 is an abundant number, since it is smaller than the sum of its proper divisors (1498302360).

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

642128040 is a wasteful number, since it uses less digits than its factorization.

642128040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 594583 (or 594573 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 27.

The square root of 642128040 is about 25340.2454605318. The cubic root of 642128040 is about 862.7279699850.

Adding to 642128040 its reverse (40821246), we get a palindrome (682949286).

The spelling of 642128040 in words is "six hundred forty-two million, one hundred twenty-eight thousand, forty".