639701 has 2 divisors, whose sum is σ = 639702. Its totient is φ = 639700.

The previous prime is 639697. The next prime is 639703. The reversal of 639701 is 107936.

It is a happy number.

639701 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 358801 + 280900 = 599^2 + 530^2 .

It is a cyclic number.

It is not a de Polignac number, because 639701 - 2² = 639697 is a prime.

Together with 639703, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (639703) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319850 + 319851.

It is an arithmetic number, because the mean of its divisors is an integer number (319851).

2⁶³⁹⁷⁰¹ is an apocalyptic number.

It is an amenable number.

639701 is a deficient number, since it is larger than the sum of its proper divisors (1).

639701 is an equidigital number, since it uses as much as digits as its factorization.

639701 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1134, while the sum is 26.

The square root of 639701 is about 799.8131031685. The cubic root of 639701 is about 86.1639651780.

The spelling of 639701 in words is "six hundred thirty-nine thousand, seven hundred one".