639940001 has 8 divisors (see below), whose sum is σ = 643713408. Its totient is φ = 636174000.

The previous prime is 639939997. The next prime is 639940009. The reversal of 639940001 is 100049936.

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

It is a cyclic number.

It is not a de Polignac number, because 639940001 - 2² = 639939997 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 639940001.

It is not an unprimeable number, because it can be changed into a prime (639940009) 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 7 ways as a sum of consecutive naturals, for example, 341096 + ... + 342966.

It is an arithmetic number, because the mean of its divisors is an integer number (80464176).

Almost surely, 2^639940001 is an apocalyptic number.

It is an amenable number.

639940001 is a deficient number, since it is larger than the sum of its proper divisors (3773407).

639940001 is a wasteful number, since it uses less digits than its factorization.

639940001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3703.

The product of its (nonzero) digits is 5832, while the sum is 32.

The square root of 639940001 is about 25297.0354191949. The cubic root of 639940001 is about 861.7469451864.

Adding to 639940001 its reverse (100049936), we get a palindrome (739989937).

The spelling of 639940001 in words is "six hundred thirty-nine million, nine hundred forty thousand, one".