642918 has 16 divisors (see below), whose sum is σ = 1302336. Its totient is φ = 211560.

The previous prime is 642907. The next prime is 642931. The reversal of 642918 is 819246.

It is a nialpdrome in base 15.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 642918.

It is an unprimeable number.

642918 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 148 + ... + 1143.

It is an arithmetic number, because the mean of its divisors is an integer number (81396).

2⁶⁴²⁹¹⁸ is an apocalyptic number.

642918 is an abundant number, since it is smaller than the sum of its proper divisors (659418).

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

642918 is a wasteful number, since it uses less digits than its factorization.

642918 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1379.

The product of its digits is 3456, while the sum is 30.

The square root of 642918 is about 801.8216759355. The cubic root of 642918 is about 86.3081607298.

It can be divided in two parts, 6 and 42918, that added together give a palindrome (42924).

The spelling of 642918 in words is "six hundred forty-two thousand, nine hundred eighteen".