642561 has 8 divisors (see below), whose sum is σ = 901920. Its totient is φ = 405792.

The previous prime is 642557. The next prime is 642563. The reversal of 642561 is 165246.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 642561 - 2² = 642557 is a prime.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 642561.

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 7 ways as a sum of consecutive naturals, for example, 5580 + ... + 5693.

It is an arithmetic number, because the mean of its divisors is an integer number (112740).

2⁶⁴²⁵⁶¹ is an apocalyptic number.

It is an amenable number.

642561 is a deficient number, since it is larger than the sum of its proper divisors (259359).

642561 is a wasteful number, since it uses less digits than its factorization.

642561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11295.

The product of its digits is 1440, while the sum is 24.

The square root of 642561 is about 801.5990269455. The cubic root of 642561 is about 86.2921826848.

The spelling of 642561 in words is "six hundred forty-two thousand, five hundred sixty-one".