639903101 has 4 divisors (see below), whose sum is σ = 640003104. Its totient is φ = 639803100.

The previous prime is 639903059. The next prime is 639903107. The reversal of 639903101 is 101309936.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 639903101 - 2¹⁸ = 639640957 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639903107) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 39695 + ... + 53436.

It is an arithmetic number, because the mean of its divisors is an integer number (160000776).

Almost surely, 2^639903101 is an apocalyptic number.

It is an amenable number.

639903101 is a deficient number, since it is larger than the sum of its proper divisors (100003).

639903101 is an equidigital number, since it uses as much as digits as its factorization.

639903101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100002.

The product of its (nonzero) digits is 4374, while the sum is 32.

The square root of 639903101 is about 25296.3060742078. The cubic root of 639903101 is about 861.7303816161.

The spelling of 639903101 in words is "six hundred thirty-nine million, nine hundred three thousand, one hundred one".