642985 has 8 divisors (see below), whose sum is σ = 881856. Its totient is φ = 440880.

The previous prime is 642977. The next prime is 642997. The reversal of 642985 is 589246.

It is a happy number.

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

It is not a de Polignac number, because 642985 - 2³ = 642977 is a prime.

It is a Duffinian number.

642985 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 642985.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9151 + ... + 9220.

It is an arithmetic number, because the mean of its divisors is an integer number (110232).

2⁶⁴²⁹⁸⁵ is an apocalyptic number.

It is an amenable number.

642985 is a deficient number, since it is larger than the sum of its proper divisors (238871).

642985 is a wasteful number, since it uses less digits than its factorization.

642985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18383.

The product of its digits is 17280, while the sum is 34.

The square root of 642985 is about 801.8634547103. The cubic root of 642985 is about 86.3111587513.

The spelling of 642985 in words is "six hundred forty-two thousand, nine hundred eighty-five".