642993 has 8 divisors (see below), whose sum is σ = 923328. Its totient is φ = 395664.

The previous prime is 642977. The next prime is 642997. The reversal of 642993 is 399246.

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

It is not a de Polignac number, because 642993 - 2⁴ = 642977 is a prime.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an Ulam number.

It is a d-powerful number, because it can be written as 6² + 4² + 9⁵ + 2¹⁵ + 9⁶ + 3⁹ .

642993 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (642997) 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, 8205 + ... + 8282.

It is an arithmetic number, because the mean of its divisors is an integer number (115416).

2⁶⁴²⁹⁹³ is an apocalyptic number.

It is an amenable number.

642993 is a deficient number, since it is larger than the sum of its proper divisors (280335).

642993 is a wasteful number, since it uses less digits than its factorization.

642993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16503.

The product of its digits is 11664, while the sum is 33.

The square root of 642993 is about 801.8684430753. The cubic root of 642993 is about 86.3115167101.

The spelling of 642993 in words is "six hundred forty-two thousand, nine hundred ninety-three".