642878287 has 8 divisors (see below), whose sum is σ = 655407936. Its totient is φ = 630363552.

The previous prime is 642878261. The next prime is 642878297. The reversal of 642878287 is 782878246.

642878287 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-642878287 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642878297) 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, 127213 + ... + 132169.

It is an arithmetic number, because the mean of its divisors is an integer number (81925992).

Almost surely, 2^642878287 is an apocalyptic number.

642878287 is a deficient number, since it is larger than the sum of its proper divisors (12529649).

642878287 is a wasteful number, since it uses less digits than its factorization.

642878287 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7457.

The product of its digits is 2408448, while the sum is 52.

The square root of 642878287 is about 25355.0446065472. The cubic root of 642878287 is about 863.0638361020.

The spelling of 642878287 in words is "six hundred forty-two million, eight hundred seventy-eight thousand, two hundred eighty-seven".