642813 has 8 divisors (see below), whose sum is σ = 860928. Its totient is φ = 426624.

The previous prime is 642809. The next prime is 642833. The reversal of 642813 is 318246.

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 642813 - 2² = 642809 is a prime.

642813 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642833) 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, 756 + ... + 1362.

It is an arithmetic number, because the mean of its divisors is an integer number (107616).

2⁶⁴²⁸¹³ is an apocalyptic number.

It is an amenable number.

642813 is a deficient number, since it is larger than the sum of its proper divisors (218115).

642813 is a wasteful number, since it uses less digits than its factorization.

642813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 963.

The product of its digits is 1152, while the sum is 24.

The square root of 642813 is about 801.7561973568. The cubic root of 642813 is about 86.3034619189.

It can be divided in two parts, 6428 and 13, that added together give a triangular number (6441 = T₁₁₃).

The spelling of 642813 in words is "six hundred forty-two thousand, eight hundred thirteen".