642569 has 4 divisors (see below), whose sum is σ = 653520. Its totient is φ = 631620.

The previous prime is 642563. The next prime is 642581. The reversal of 642569 is 965246.

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 a cyclic number.

It is not a de Polignac number, because 642569 - 2¹⁶ = 577033 is a prime.

It is a super-2 number, since 2×642569² = 825789839522, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 642569.

It is not an unprimeable number, because it can be changed into a prime (642563) 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, 5387 + ... + 5504.

It is an arithmetic number, because the mean of its divisors is an integer number (163380).

2⁶⁴²⁵⁶⁹ is an apocalyptic number.

It is an amenable number.

642569 is a deficient number, since it is larger than the sum of its proper divisors (10951).

642569 is a wasteful number, since it uses less digits than its factorization.

642569 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10950.

The product of its digits is 12960, while the sum is 32.

The square root of 642569 is about 801.6040169560. The cubic root of 642569 is about 86.2925408010.

The spelling of 642569 in words is "six hundred forty-two thousand, five hundred sixty-nine".