642521 has 4 divisors (see below), whose sum is σ = 700944. Its totient is φ = 584100.

The previous prime is 642517. The next prime is 642527. The reversal of 642521 is 125246.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 642521 - 2² = 642517 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 642493 and 642502.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 642521.

It is not an unprimeable number, because it can be changed into a prime (642527) 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, 29195 + ... + 29216.

It is an arithmetic number, because the mean of its divisors is an integer number (175236).

2⁶⁴²⁵²¹ is an apocalyptic number.

It is an amenable number.

642521 is a deficient number, since it is larger than the sum of its proper divisors (58423).

642521 is a wasteful number, since it uses less digits than its factorization.

642521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58422.

The product of its digits is 480, while the sum is 20.

The square root of 642521 is about 801.5740764271. The cubic root of 642521 is about 86.2903920590.

Adding to 642521 its reverse (125246), we get a palindrome (767767).

It can be divided in two parts, 6425 and 21, that added together give a palindrome (6446).

The spelling of 642521 in words is "six hundred forty-two thousand, five hundred twenty-one".