642489 has 4 divisors (see below), whose sum is σ = 856656. Its totient is φ = 428324.

The previous prime is 642487. The next prime is 642517. The reversal of 642489 is 984246.

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 642489 - 2¹ = 642487 is a prime.

It is a D-number.

642489 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (642487) 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, 107079 + ... + 107084.

It is an arithmetic number, because the mean of its divisors is an integer number (214164).

2⁶⁴²⁴⁸⁹ is an apocalyptic number.

It is an amenable number.

642489 is a deficient number, since it is larger than the sum of its proper divisors (214167).

642489 is a wasteful number, since it uses less digits than its factorization.

642489 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 214166.

The product of its digits is 13824, while the sum is 33.

The square root of 642489 is about 801.5541154532. The cubic root of 642489 is about 86.2889595048.

The spelling of 642489 in words is "six hundred forty-two thousand, four hundred eighty-nine".