639381401 has 8 divisors (see below), whose sum is σ = 646818504. Its totient is φ = 631987200.

The previous prime is 639381397. The next prime is 639381403. The reversal of 639381401 is 104183936.

639381401 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 50176 + 639331225 = 224^2 + 25285^2 .

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 639381401 - 2² = 639381397 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (639381403) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19751 + ... + 40851.

It is an arithmetic number, because the mean of its divisors is an integer number (80852313).

Almost surely, 2^639381401 is an apocalyptic number.

It is an amenable number.

639381401 is a deficient number, since it is larger than the sum of its proper divisors (7437103).

639381401 is a wasteful number, since it uses less digits than its factorization.

639381401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21451.

The product of its (nonzero) digits is 15552, while the sum is 35.

The square root of 639381401 is about 25285.9921893526. The cubic root of 639381401 is about 861.4961341869.

The spelling of 639381401 in words is "six hundred thirty-nine million, three hundred eighty-one thousand, four hundred one".