642824641 has 4 divisors (see below), whose sum is σ = 651630532. Its totient is φ = 634018752.

The previous prime is 642824579. The next prime is 642824657. The reversal of 642824641 is 146428246.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 246615616 + 396209025 = 15704^2 + 19905^2 .

It is a cyclic number.

It is not a de Polignac number, because 642824641 - 2⁷ = 642824513 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 642824641.

It is not an unprimeable number, because it can be changed into a prime (642824671) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4402836 + ... + 4402981.

It is an arithmetic number, because the mean of its divisors is an integer number (162907633).

Almost surely, 2^642824641 is an apocalyptic number.

It is an amenable number.

642824641 is a deficient number, since it is larger than the sum of its proper divisors (8805891).

642824641 is an equidigital number, since it uses as much as digits as its factorization.

642824641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8805890.

The product of its digits is 73728, while the sum is 37.

The square root of 642824641 is about 25353.9866884875. The cubic root of 642824641 is about 863.0398288565.

The spelling of 642824641 in words is "six hundred forty-two million, eight hundred twenty-four thousand, six hundred forty-one".