642131 has 4 divisors (see below), whose sum is σ = 733872. Its totient is φ = 550392.

The previous prime is 642121. The next prime is 642133. The reversal of 642131 is 131246.

642131 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-642131 is a prime.

It is a super-2 number, since 2×642131² = 824664442322, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 642131.

It is not an unprimeable number, because it can be changed into a prime (642133) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45860 + ... + 45873.

It is an arithmetic number, because the mean of its divisors is an integer number (183468).

2⁶⁴²¹³¹ is an apocalyptic number.

642131 is a deficient number, since it is larger than the sum of its proper divisors (91741).

642131 is an equidigital number, since it uses as much as digits as its factorization.

642131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91740.

The product of its digits is 144, while the sum is 17.

The square root of 642131 is about 801.3307681601. The cubic root of 642131 is about 86.2729295614.

Adding to 642131 its reverse (131246), we get a palindrome (773377).

The spelling of 642131 in words is "six hundred forty-two thousand, one hundred thirty-one".