642996 has 36 divisors (see below), whose sum is σ = 1660932. Its totient is φ = 209664.

The previous prime is 642977. The next prime is 642997. The reversal of 642996 is 699246.

642996 is a `hidden beast` number, since 642 + 9 + 9 + 6 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 318096 + 324900 = 564^2 + 570^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 642996.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642997) by changing a digit.

642996 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1740 + ... + 2076.

It is an arithmetic number, because the mean of its divisors is an integer number (46137).

2⁶⁴²⁹⁹⁶ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 642996, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (830466).

642996 is an abundant number, since it is smaller than the sum of its proper divisors (1017936).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

642996 is a wasteful number, since it uses less digits than its factorization.

642996 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 400 (or 395 counting only the distinct ones).

The product of its digits is 23328, while the sum is 36.

The square root of 642996 is about 801.8703137042. The cubic root of 642996 is about 86.3116509439.

The spelling of 642996 in words is "six hundred forty-two thousand, nine hundred ninety-six".