642847 has 8 divisors (see below), whose sum is σ = 673920. Its totient is φ = 612480.

The previous prime is 642833. The next prime is 642853. The reversal of 642847 is 748246.

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-642847 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642877) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2643 + ... + 2875.

It is an arithmetic number, because the mean of its divisors is an integer number (84240).

2⁶⁴²⁸⁴⁷ is an apocalyptic number.

642847 is a deficient number, since it is larger than the sum of its proper divisors (31073).

642847 is a wasteful number, since it uses less digits than its factorization.

642847 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 353.

The product of its digits is 10752, while the sum is 31.

The square root of 642847 is about 801.7774005296. Note that the first 3 decimals coincide. The cubic root of 642847 is about 86.3049834947.

The spelling of 642847 in words is "six hundred forty-two thousand, eight hundred forty-seven".