639009001 has 2 divisors, whose sum is σ = 639009002. Its totient is φ = 639009000.

The previous prime is 639008989. The next prime is 639009089. The reversal of 639009001 is 100900936.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 487349776 + 151659225 = 22076^2 + 12315^2 .

It is a cyclic number.

It is not a de Polignac number, because 639009001 - 2¹³ = 639000809 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (639009401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319504500 + 319504501.

It is an arithmetic number, because the mean of its divisors is an integer number (319504501).

Almost surely, 2^639009001 is an apocalyptic number.

It is an amenable number.

639009001 is a deficient number, since it is larger than the sum of its proper divisors (1).

639009001 is an equidigital number, since it uses as much as digits as its factorization.

639009001 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1458, while the sum is 28.

The square root of 639009001 is about 25278.6273559305. The cubic root of 639009001 is about 861.3288456868.

Adding to 639009001 its reverse (100900936), we get a palindrome (739909937).

The spelling of 639009001 in words is "six hundred thirty-nine million, nine thousand, one".