642571 has 4 divisors (see below), whose sum is σ = 646000. Its totient is φ = 639144.

The previous prime is 642563. The next prime is 642581. The reversal of 642571 is 175246.

642571 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, and also an emirpimes, since its reverse is a distinct semiprime: 175246 = 2 ⋅87623.

It is a cyclic number.

It is not a de Polignac number, because 642571 - 2³ = 642563 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (642581) 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, 1416 + ... + 1813.

It is an arithmetic number, because the mean of its divisors is an integer number (161500).

2⁶⁴²⁵⁷¹ is an apocalyptic number.

642571 is a deficient number, since it is larger than the sum of its proper divisors (3429).

642571 is a wasteful number, since it uses less digits than its factorization.

642571 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3428.

The product of its digits is 1680, while the sum is 25.

The square root of 642571 is about 801.6052644538. The cubic root of 642571 is about 86.2926303296.

The spelling of 642571 in words is "six hundred forty-two thousand, five hundred seventy-one".