642730 has 16 divisors (see below), whose sum is σ = 1262304. Its totient is φ = 233680.

The previous prime is 642701. The next prime is 642737. The reversal of 642730 is 37246.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is not an unprimeable number, because it can be changed into a prime (642737) by changing a digit.

642730 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2812 + ... + 3031.

It is an arithmetic number, because the mean of its divisors is an integer number (78894).

2⁶⁴²⁷³⁰ is an apocalyptic number.

642730 is a deficient number, since it is larger than the sum of its proper divisors (619574).

642730 is a wasteful number, since it uses less digits than its factorization.

642730 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5861.

The product of its (nonzero) digits is 1008, while the sum is 22.

The square root of 642730 is about 801.7044343148. The cubic root of 642730 is about 86.2997472587.

Adding to 642730 its reverse (37246), we get a palindrome (679976).

The spelling of 642730 in words is "six hundred forty-two thousand, seven hundred thirty".