642178840 has 32 divisors (see below), whose sum is σ = 1454484960. Its totient is φ = 255168000.

The previous prime is 642178829. The next prime is 642178843. The reversal of 642178840 is 48871246.

642178840 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 642178793 and 642178802.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642178843) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 47121 + ... + 59200.

It is an arithmetic number, because the mean of its divisors is an integer number (45452655).

Almost surely, 2^642178840 is an apocalyptic number.

It is an amenable number.

642178840 is an abundant number, since it is smaller than the sum of its proper divisors (812306120).

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

642178840 is a wasteful number, since it uses less digits than its factorization.

642178840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106483 (or 106479 counting only the distinct ones).

The product of its (nonzero) digits is 86016, while the sum is 40.

The square root of 642178840 is about 25341.2477987963. The cubic root of 642178840 is about 862.7507200818.

The spelling of 642178840 in words is "six hundred forty-two million, one hundred seventy-eight thousand, eight hundred forty".