642553 has 4 divisors (see below), whose sum is σ = 664740. Its totient is φ = 620368.

The previous prime is 642547. The next prime is 642557. The reversal of 642553 is 355246.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 355246 = 2 ⋅177623.

It can be written as a sum of positive squares in 2 ways, for example, as 451584 + 190969 = 672^2 + 437^2 .

It is a de Polignac number, because none of the positive numbers 2^k-642553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (642557) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11050 + ... + 11107.

It is an arithmetic number, because the mean of its divisors is an integer number (166185).

2⁶⁴²⁵⁵³ is an apocalyptic number.

It is an amenable number.

642553 is a deficient number, since it is larger than the sum of its proper divisors (22187).

642553 is a wasteful number, since it uses less digits than its factorization.

642553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22186.

The product of its digits is 3600, while the sum is 25.

The square root of 642553 is about 801.5940369040. The cubic root of 642553 is about 86.2918245656.

Adding to 642553 its reverse (355246), we get a palindrome (997799).

The spelling of 642553 in words is "six hundred forty-two thousand, five hundred fifty-three".